Check for RevisionableEntityBundleInterface in og_ui_form_alter

Closes #3469354

og_ui/og_ui.module

@@ -10,6 +10,7 @@ declare(strict_types=1);
 use Drupal\Core\Config\Entity\ConfigEntityBundleBase;
 use Drupal\Core\Entity\BundleEntityFormBase;
 use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\RevisionableEntityBundleInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\field\Entity\FieldStorageConfig;
@@ -24,9 +25,15 @@ function og_ui_form_alter(array &$form, FormStateInterface $form_state, $form_id
     return;
   }
 
-  $entity_type = $form_state->getFormObject()->getEntity();
+  $entity = $form_state->getFormObject()->getEntity();
+
+  // Avoid entities like webform and commerce_product.
+  if (!$entity instanceof RevisionableEntityBundleInterface) {
+    return;
+  }
+
   // To avoid insanity, a group membership cannot be a group or group content.
-  if ($entity_type->getEntityTypeId() === 'og_membership_type') {
+  if ($entity->getEntityTypeId() === 'og_membership_type') {
     return;
   }