Fix Invalid Argument Exception: The Step EMPTY STRING does not exist in forms steps [#3320087]

Problem/Motivation

InvalidArgumentException: The Step '' does not exist in forms steps 'project' in Drupal\forms_steps\Entity\FormsSteps->getStep() (line 425 of /app/docroot/modules/contrib/forms_steps/src/Entity/FormsSteps.php).

Steps to reproduce

Given that I have activated the steps of the form on the "Project" content type
And had a number of steps configured
When I go to the steps
And save the step
Then the following error shows up

#0 /app/docroot/modules/contrib/forms_steps/src/Plugin/Block/FormsStepsProgressBarBlock.php(140): Drupal\forms_steps\Entity\FormsSteps->getStep(NULL)
#1 /app/docroot/core/modules/block/src/BlockViewBuilder.php(171): Drupal\forms_steps\Plugin\Block\FormsStepsProgressBarBlock->build()
#2 [internal function]: Drupal\block\BlockViewBuilder::preRender(Array)
#3 /app/docroot/core/lib/Drupal/Core/Security/DoTrustedCallbackTrait.php(101): call_user_func_array(Array, Array)
#4 /app/docroot/core/lib/Drupal/Core/Render/Renderer.php(772): Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_ren...', 'exception', 'Drupal\\Core\\Ren...')
#5 /app/docroot/core/lib/Drupal/Core/Render/Renderer.php(363): Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array)
#6 /app/docroot/core/lib/Drupal/Core/Render/Renderer.php(435): Drupal\Core\Render\Renderer->doRender(Array)
#7 /app/docroot/core/lib/Drupal/Core/Render/Renderer.php(201): Drupal\Core\Render\Renderer->doRender(Array, false)
#8 /app/docroot/core/lib/Drupal/Core/Template/TwigExtension.php(479): Drupal\Core\Render\Renderer->render(Array)
#9 /app/vendor/twig/twig/src/Environment.php(418) : eval()'d code(80): Drupal\Core\Template\TwigExtension->escapeFilter(Object(Drupal\Core\Template\TwigEnvironment), Array, 'html', NULL, true)
#10 /app/vendor/twig/twig/src/Template.php(405): __TwigTemplate_3a769198b6774d563f79959d3397976d->doDisplay(Array, Array)
#11 /app/vendor/twig/twig/src/Template.php(378): Twig\Template->displayWithErrorHandling(Array, Array)
#12 /app/vendor/twig/twig/src/Template.php(390): Twig\Template->display(Array)
#13 /app/docroot/core/themes/engines/twig/twig.engine(55): Twig\Template->render(Array)
#14 /app/docroot/core/lib/Drupal/Core/Theme/ThemeManager.php(384): twig_render_template('core/themes/cla...', Array)
#15 /app/docroot/core/lib/Drupal/Core/Render/Renderer.php(422): Drupal\C...