Recompile test env Gitaly when `GITALY_SERVER_VERSION` fails

What does this MR do?

Fetch and compile Gitaly whenever the GITALY_SERVER_VERSION doesn't match the version of the test instance.

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

No

Why was this MR needed?

Some developers were randomly getting spec errors because of mismatched Gitaly versions

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• 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 #32762 (closed)

/cc @andrewn @jacobvosmaer-gitlab