Disable logging of gRPC Health RPC messages

What does this Merge Request do and why?

Health checks dominate the log output of gdk tail, making it difficult to watch other activity.

gitaly!4168 (merged) added the ability to filter out gRPC messages. We use this feature to suppress the output of health checks.

gitaly#3428 (closed) is open for discussing whether this should be the default mode.

Merge Request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise Issue to follow-up.
• Documentation added/updated, if needed.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.