Respect `ref` when searching for commits

What does this MR do?

In #199245 (closed), a bug was noticed in the Search API when searching for commits in a ref.

The search returns results from the default branch (master) regardless of what ref is provided. The same bug also applies to web search. The issue also affects Advanced Search, since searching for commits in a ref other than master falls back to non-ES search.

This MR solves this issue by passing ref through to Gitaly when searching for commits.

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
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team