fix: register controller workqueue metrics correctly

[yeya24]

Signed-off-by: Ben Ye ben.ye@bytedance.com

Fixes: #7682.

Note on DCO:

If the DCO action in the integration test fails, one or more of your commits are not signed off. Please click on the Details link next to the DCO action for instructions on how to resolve this.

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• Optional. My organization is added to USERS.md.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).

Verification

[codecov]

Codecov Report

Merging #8318 (327a33e) into master (85c114d) will decrease coverage by 0.00%.
The diff coverage is 22.22%.

@@            Coverage Diff             @@
##           master    #8318      +/-   ##
==========================================
- Coverage   41.91%   41.91%   -0.01%     
==========================================
  Files         176      178       +2     
  Lines       22992    23003      +11     
==========================================
+ Hits         9637     9641       +4     
- Misses      11972    11979       +7     
  Partials     1383     1383              

Impacted Files	Coverage Δ
controller/appcontroller.go	51.82% <ø> (ø)
controller/metrics/workqueue.go	12.50% <12.50%> (ø)
controller/metrics/metrics.go	80.13% <100.00%> (+0.13%)	⬆️
cmpserver/plugin/plugin.go	51.92% <0.00%> (ø)
cmpserver/plugin/plugin_unix.go	100.00% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 85c114d...327a33e. Read the comment docs.

[alexmt]

Thank you!