Prometheus: some per-exchange/per-queue metrics aggregated per-channel (rebased) (backport #11755)

[mergify]

This is #11726 rebased. Submitting to see if CI passes with Bazel and GCP-based Bazel caching.

---

This is an automatic backport of pull request #11755 done by Mergify.

[mergify]

Cherry-pick of c66e5ea has failed:

On branch mergify/bp/v4.0.x/pr-11755
Your branch is ahead of 'origin/v4.0.x' by 1 commit.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit c66e5ea058.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   release-notes/4.0.0.md

no changes added to commit (use "git add" and/or "git commit -a")

Cherry-pick of a931cec has failed:

On branch mergify/bp/v4.0.x/pr-11755
Your branch is ahead of 'origin/v4.0.x' by 2 commits.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit a931cec76e.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   release-notes/4.0.0.md

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally