Decorate 'menu.parent_form_selector' instead of overwriting with service provider

Also attaching the patch for easier usage in composer based projects.

The last submitted patch, 3: 3444489-decorate-service-3.patch, failed testing. View results →
- codesniffer_fixes.patch Interdiff of automated coding standards fixes only.

Small adjustments to the patch and MR because of this issue https://www.drupal.org/project/group_content_menu/issues/3417879 🐛 Can't create group menu link after upgrade to 10.2.2 - Error: Call to a member function label() on null Closed: duplicate and related core issue https://www.drupal.org/project/drupal/issues/3411384 🐛 Error: Call to a member function label() on null in Drupal\menu_link_content\Form\MenuLinkContentForm->form() (line 99 of /var/www/html/docroot/core/modules/menu_link_content/src/Form/MenuLinkContentForm.php). Fixed . Interdiff https://git.drupalcode.org/project/group_content_menu/-/merge_requests/2...

Referenced issue in menu_select module was fixed.

Automatically closed - issue fixed for 2 weeks with no activity.