Convert bootstrap alert for project size limit

- add changelog

ee/app/views/projects/_above_size_limit_warning.html.haml

 - size_checker = project.repository_size_checker
 - if size_checker.above_size_limit?
-  .alert.alert-warning.d-none.d-sm-block
+  .gl-alert.gl-alert-warning.gl-display-none.gl-display-sm-block
+    = sprite_icon('warning', size: 16, css_class: 'gl-icon gl-alert-icon gl-alert-icon-no-title')
     = size_checker.error_message.above_size_limit_message

ee/changelogs/unreleased/233682-bootstrap-alert-size-limit.yml

+---
+title: Convert bootstrap alert to gl for project size limit
+merge_request: 45312
+author:
+type: other