add panel Query Concurrency to dashboard mixin.

[raptorsun]

• [ ] I added CHANGELOG entry for this change.
• [x] Change is not relevant to the end user.

Changes

add a panel "Query Concurrency" to the dashboard mixin, showing the available capacity to serve concurrent queries.

Verification

add the dashboard to grafana to check it.

The panel should look like this:

[raptorsun]

how to rerun the failing test? it seems like a transient error.

[douglascamata]

Hey @raptorsun, can you have a look at the feedback so that we can proceed with merging your contribution, please? 🙏

To rerun the build in case it fails, you can push an empty commit. Here's how you can create an empty commit: git commit -s --allow-empty -m "Empty commit to trigger CI"

[douglascamata]

Small tip: maybe rebasing with main can help reducing the random failures. We've been working on this recently.

[raptorsun]

Small tip: maybe rebasing with main can help reducing the random failures. We've been working on this recently.

The PR has been rebased on latest main branch now.