Resolve "QA: False failure on QA test "Push to protected branch when allowed" during staging failover rehearsal"

What does this MR do?

This ensure the external encoding is set to UTF-8 when running QA specs.

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

If QA passes I guess that's it.

Does this MR meet the acceptance criteria?

• Conform by the code review guidelines
  • Has been reviewed by a Backend maintainer
• Conform by the merge request performance guides
• Conform by the style guides
• Conform by the database guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #48241 (closed)