Resolve ""You can also press Ctrl-Enter" tooltip lingers after Tab+Enter"

What does this MR do?

Hides the hotkey tooltip when the diff comment form is submitted via "tab+enter".

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

No.

Why was this MR needed?

Improve the UX of the diff comments in Merge Requests, you can have multiple tooltips stuck on the page with this bug.

Screenshots (if relevant)

Before: 37211-Before

After: 37211-After

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes #37211 (closed)