Breaking error on webforms that do not use forward navigation

Problem/Motivation

I keep getting the following error on webforms that do not use the webformnavigation module to add forward navigation:

PHP errors logged to watchdog in scenario Owner can fill out the Itchy Dog Questionnaire.stdClass Object
(
    [wid] => 140
    [uid] => 96
    [type] => php
    [message] => %type: @message in %function (line %line of %file) @backtrace_string.
    [variables] => Array
        (
            [%type] => TypeError
            [@message] => Argument 1 passed to Drupal\webformnavigation\WebformNavigationHelper::getErrors() must implement interface Drupal\webform\WebformSubmissionInterface, null given, called in /var/www/html/docroot/modules/contrib/webformnavigation/webformnavigation.module on line 68
            [%function] => Drupal\webformnavigation\WebformNavigationHelper->getErrors()
            [%file] => /var/www/html/docroot/modules/contrib/webformnavigation/src/WebformNavigationHelper.php
            [%line] => 152
            [@backtrace_string] => #0 /var/www/html/docroot/modules/contrib/webformnavigation/webformnavigation.module(68): Drupal\webformnavigation\WebformNavigationHelper->getErrors(NULL)
#1 /var/www/html/docroot/core/lib/Drupal/Core/Theme/ThemeManager.php(287): webformnavigation_preprocess_webform_progress_tracker(Array, 'webform_progres...', Array)
#2 /var/www/html/docroot/core/lib/Drupal/Core/Render/Renderer.php(422): Drupal\Core\Theme\ThemeManager->render('webform_progres...', Array)
#3 /var/www/html/docroot/core/lib/Drupal/Core/Render/Renderer.php(201): Drupal\Core\Render\Renderer->doRender(Array, false)
#4 /var/www/html/docroot/core/lib/Drupal/Core/Template/TwigExtension.php(479): Drupal\Core\Render\Renderer->render(Array)
#5 /var/www/html/docroot/sites/default/files/php/twig/6241e4ae3fac4_webform-progress.html.twi_3kfxcORrP7BUSY1-aNsFOIEBH/NVwINoHitxHOXM70fVq56VrXYLf5UxT1bvvHYQptU6A.php(46): Drupal\Core\Template\TwigExtension->escapeFilter(Object(Drupal\Core\Template\TwigEnvironment), Array, 'html', NULL, true)
#6 /var/www/html/vendor/twig/twig/src/Template.php(405): __TwigTemplate_56e73ff5e79b6cadef1395e7bdb4600d9eb456ebc74d531be186da1ffbac3d14->doDisplay(Array, Array)
#7 /var/www/html/vendor/twig/twig/src/Template.php(378): Twig\Template->displayWithErrorHandling(Array, Array)
#8 /var/www/html/vendor/twig/twig/src/Template.php(390): Twig\Template->display(Array)
#9 /var/www/html/docroot/core/themes/engines/twig/twig.engine(55): Twig\Template->render(Array)
#10 /var/www/html/docroot/core/lib/Drupal/Core/Theme/ThemeManager.php(384): twig_render_template('modules/contrib...', Array)
#11 /var/www/html/docroot/core/lib/Drupal/Core/Render/Renderer.php(422): Drupal\Core\Theme\ThemeManager->render('webform_progres...', Array)
#12 /var/www/html/docroot/core/lib/Drupal/Core/Render/Renderer.php(201): Drupal\Core\Render\Renderer->doRender(Array, false)
#13 /var/www/html/docroot/core/lib/Drupal/Core/Template/TwigExtension.php(479): Drupal\Core\Render\Renderer->render(Array)
#14 /var/www/html/docroot/sites/default/files/php/twig/6241e4ae3fac4_webform-confirmation.html_CzDnQbywdPzvV4UKLGr8Ovyvp/jbpqLPCKeHcMWlKbvD_cr9EviMNhjFzrCinWTMzGJ84.php(47): Drupal\Core\Template\TwigExtension->escapeFilter(Object(Drupal\Core\Template\TwigEnvironment), Array, 'html', NULL, true)
#15 /var/www/html/vendor/twig/twig/src/Template.php(405): __TwigTemplate_c391182800095dd2811920e2730b506372abe5737a5ba07fdc653b6fbd00ba4b->doDisplay(Array, Array)
#16 /var/www/html/vendor/twig/twig/src/Template.php(378): Twig\Template->displayWithErrorHandling(Array, Array)
#17 /var/www/html/vendor/twig/twig/src/Template.php(390): Twig\Template->display(Array)
#18 /var/www/html/docroot/core/themes/engines/twig/twig.engine(55): Twig\Template->render(Array)
#19 /var/www/html/docroot/core/lib/Drupal/Core/Theme/ThemeManager.php(384): twig_render_template('modules/contrib...', Array)
#20 /var/www/html/docroot/core/lib/Drupal/Core/Render/Renderer.php(422): Drupal\Core\Theme\ThemeManager->render('webform_confirm...', Array)
#21 /var/www/html/docroot/core/lib/Drupal/Core/Render/Renderer.php(201): Drupal\Core\Render\Renderer->doRender(Array, false)
#22 /var/www/html/docroot/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php(241): Drupal\Core\Render\Renderer->render(Array, false)
#23 /var/www/html/docroot/core/lib/Drupal/Core/Render/Renderer.php(564): Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}()
#24 /var/www/html/docroot/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php(242): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure))
#25 /var/www/html/docroot/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php(132): Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\CurrentRouteMatch))
#26 /var/www/html/docroot/core/lib/Drupal/Core/EventSubscriber/MainContentViewSubscriber.php(90): Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\CurrentRouteMatch))
#27 [internal function]: Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object(Symfony\Component\HttpKernel\Event\ViewEvent), 'kernel.view', Object(Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher))
#28 /var/www/html/docroot/core/lib/Drupal/Component/EventDispatcher/ContainerAwareEventDispatcher.php(142): call_user_func(Array, Object(Symfony\Component\HttpKernel\Event\ViewEvent), 'kernel.view', Object(Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher))
#29 /var/www/html/vendor/symfony/http-kernel/HttpKernel.php(163): Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object(Symfony\Component\HttpKernel\Event\ViewEvent), 'kernel.view')
#30 /var/www/html/vendor/symfony/http-kernel/HttpKernel.php(80): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1)
#31 /var/www/html/docroot/core/lib/Drupal/Core/StackMiddleware/Session.php(58): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#32 /var/www/html/docroot/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(48): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#33 /var/www/html/docroot/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#34 /var/www/html/docroot/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#35 /var/www/html/vendor/asm89/stack-cors/src/Asm89/Stack/Cors.php(49): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#36 /var/www/html/docroot/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(48): Asm89\Stack\Cors->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#37 /var/www/html/docroot/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(51): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#38 /var/www/html/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#39 /var/www/html/docroot/core/lib/Drupal/Core/DrupalKernel.php(708): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#40 /var/www/html/docroot/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request))
#41 {main}
        )
    [severity] => 3
    [link] =>
    [location] => http://web/questionnaire/canine-atopic-dermatitis-research/confirmation?unique_id=094-000284
    [referer] => http://web/questionnaire/canine-atopic-dermatitis-research?unique_id=094-000284
    [hostname] => 172.27.0.3
    [timestamp] => 1648485580
)

Steps to reproduce

1. Enable the webformnavigation module on a vanilla build of Drupal
2. Create a multi-page webform with a confirmation page that uses forward navigation
3. Create a multi-page webform with a confirmation page and the progress bar that doesn't us forward navigation
4. Notice that you get the error when you navigate to the second webforms confirmation page or when you complete the second webform

Proposed resolution

Add a check to the helper function that ensures forward navigation is enabled on a form and returns NULL if a submission is not supplied.