Expire protected branches cache after branch cache expiration

What does this MR do and why?

• Contributes to #366724 (closed)
• Feature flag: #368279 (comment 1058594744)

Problem

Testing of protected branches cache discovered a missing use-case for expiration logic. When the new branch is created, we should expire cache for protected branches too.

Solution

Extend expire_branches_cache logic with expiration of protected branches cache.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.