Hide description about protected branches to non-member

What does this MR do?

Makes a description about protected branches hidden to a non-member.

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

No.

Why was this MR needed?

A message for admin is not always useful in general and a link in this message will be 404 error for non-members.

Screenshots

description	screenshot
before
after (member)
after (non-member)

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
  • 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 #35253 (closed)