Fixes builds dropdown making request when clicked to be closed

What does this MR do?

Uses the bootstrap dropdown event to make the request instead of making it every time we click the dropdown. This way the request is only made once.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Every time the dropdown builds in the mini-pipeline graph button is clicked a request to get the stages is made, with this MR is fixed

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #26601 (closed)