Issue #3412960 by DYdave: GitLab CI: Fixed Composer job failing due to project...

https://www.drupal.org/project/structure_sync/issues/3412960

Autmated Tests: Fixed GitLab CI errors:

• Composer job failing due to project root Drush version requirements, by adding version constraint to allow drush:^12.
• PHPUnit FunctionalJavascript tests failing due to RuntimeException: Unable to complete AJAX request. by replacing calls to assertWaitOnAjaxRequest with waitForElementVisible.
• Fixed regression from Drupal.org, Issues for Structure Sync: Import breaks when no menu's have been exported (patch available), introduced in commit '1eed4e0c'. Importing with no config should now print out the following log message:

$ drush import:menus --choice safe
Importing menu links...
Using "Safe" import style
 [notice] Menu links import started
 [notice] Using "safe" style for menu links import
 [notice] No menu exported: Nothing to import.
Menus need to be exported first before they can be imported.

and added corresponding test to module's DrushTests (StructureSyncMenuLinksDrushTest).