New internal endpoint for kas to increment gitops_sync_count metric

What does this MR do?

Related issue: #219716 (closed)

New internal endpoint for kas to increment gitops_sync_count metric

This metric will then be pushed onto a Redis counter. The redis counter will then be posted to usage ping later.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry, as behind a feature flag
• [-] 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.