Remove the repository_ancestor_calls_total counter

What does this MR do?

This shows that we're hitting the cache quite often, so that's an improvement:

But the counter itself doesn't add any more value. So let's give our prometheus a little break by removing some metrics.

Closes #37771 (closed)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• [-] Code review guidelines
• [-] Merge request performance guidelines
• [-] Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers