Partition job_queue_duration_seconds with jobs_running_for_project

What does this MR do?

Adds information about currently handled jobs for a project to job_queue_duration_seconds metric.

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

Why was this MR needed?

Please check #43219 (closed) for a reference.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides

What are the relevant issue numbers?

Resolves #43219 (closed)