[Drupal 11] fix: add jquery_legacy library

Problem: The current setup uses jQuery v4.0.0-beta.2 alongside Bootstrap v4.6.0.

However, Bootstrap 4 requires jQuery version ≥ 1.9.1 and < 4.0.0. Because the jQuery version is incompatible (v4.x), Bootstrap’s JavaScript plugins (e.g., $.fn.modal) are not registered, which leads to errors such as undefined when trying to use modal or other components.

How to review:

• Make sure that when click on the button open modal windows