Drupal\solr_search_synonym\Plugin\solr_search_synonym\import\CSV::parseFile(): Argument #1 ($file) must be of type Drupal\file\Entity\File, string given, called in SynonymImportForm.php on line 251 [#3537072]

Problem/Motivation

I get this error when i try to save
/admin/config/search/solr-search-synonyms/import
without upload file.

TypeError: Drupal\solr_search_synonym\Plugin\solr_search_synonym\import\Solr::parseFile(): Argument #1 ($file) must be of type Drupal\file\Entity\File, string given, called in /var/www/html/web/modules/contrib/solr_search_synonym/src/Form/SynonymImportForm.php on line 251 in Drupal\solr_search_synonym\Plugin\solr_search_synonym\import\Solr->parseFile() (line 26 of modules/contrib/solr_search_synonym/src/Plugin/solr_search_synonym/import/Solr.php).
Drupal\solr_search_synonym\Form\SynonymImportForm->submitForm(Array, Object)
call_user_func_array(Array, Array) (Line: 129)
Drupal\Core\Form\FormSubmitter->executeSubmitHandlers(Array, Object) (Line: 67)
Drupal\Core\Form\FormSubmitter->doSubmitForm(Array, Object) (Line: 597)
Drupal\Core\Form\FormBuilder->processForm('solr_search_synonym_import', Array, Object) (Line: 326)
Drupal\Core\Form\FormBuilder->buildForm(Object, Object) (Line: 73)
Drupal\Core\Controller\FormController->getContentResult(Object, Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 638)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 121)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 181)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 53)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 28)
Drupal\Core\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 32)
Drupal\big_pipe\StackMiddleware\ContentLength->handle(Object, 1, 1) (Line: 116)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 90)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 36)
Drupal\Core\StackMiddleware\AjaxPageState->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle(Object, 1, 1) (Line: 741)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)