Fix tooltip text when Copy to cliboard is clicked

What does this MR do?

Fixes #22022 (closed) to change tooltip text to "Copied!" when the "Copy to clipboard" button is clicked.

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

Line 29 in app/assets/javascripts/copy_to_clipboard.js

Why was this MR needed?

There was a regression that prevents tooltip change on button click for Copy to clipboard.

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 you do - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #22022 (closed)