Remove ahead/behind graphs on project branches on mobile

What does this MR do?

Removes ahead/behind graphs on project branches for mobile.

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

No.

Why was this MR needed?

A user does not want to see divergence graph on branches in a smaller screen on mobile devices.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

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

What are the relevant issue numbers?

Closes #42543 (closed)