Pending JS "closed.bs.alert" when closing a Bootstrap alert

Behat should take care of this

If you want to test manually:

1. Open any Moodle page (login not required)
2. Open browser developer tools => console
3. Run the following:

   M.util.pending_js; // Should return an empty array => []

   require(['core/notification'], N => N.addNotification({message: "Close me!"}));

   M.util.pending_js; // Should return an empty array => []

   1. Confirm that a new notification appear in the body of the page
4. Press the [x] button in the top-right of that notification
   1. Confirm that the notification was removed
   2. Confirm that the following code returns an empty array still:

      M.util.pending_js; // Should return an empty array => []