Issue #3432545 by mark_fullmer: AssertionError: assert($editor instanceof Editor)

core/modules/ckeditor5/src/Plugin/Editor/CKEditor5.php

@@ -261,7 +261,7 @@ public static function validatePair(EditorInterface $text_editor, FilterFormatIn
    */
   public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
     $editor = $form_state->get('editor');
-    assert($editor instanceof Editor);
+    assert($editor instanceof EditorEntity);
     $language = $this->languageManager->getCurrentLanguage();
 
     // When enabling CKEditor 5, generate sensible settings from the