Resolve "Protected branch selector not found in test"

What does this MR do?

Fixes the latest example for the protected_branches_spec to move it inside a context block where a sign happens

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Review
  • Has been reviewed by Frontend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #38835 (closed)