PHP error on webform field delete

The issue is that the getEntity() method is not implemented in all form classes — only in those that extend from ContentEntityForm.
To avoid this error, we should first check whether the form object is an instance of ContentEntityDeleteForm, or a compatible class, before calling the method.

$form_object = $form_state->getFormObject();
  if (!$form_object instanceof ContentEntityDeleteForm) {
    return;
  }

It is ready for QA.

After applying the patch, deleting a webform element works correctly.

lpeidro → changed the visibility of the branch 3526552-php-error-on to hidden.