metrics: add metrics for the internal pd client calls

[rleungx]

What problem does this PR solve?

Issue Number: Close #9039

What is changed and how does it work?

Check List

Tests

• Unit test

Release note

None.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.28%. Comparing base (d9abd06) to head (4dcadb4).
Report is 1430 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9043      +/-   ##
==========================================
+ Coverage   75.65%   76.28%   +0.62%     
==========================================
  Files         332      467     +135     
  Lines       33902    71149   +37247     
==========================================
+ Hits        25650    54276   +28626     
- Misses       6056    13494    +7438     
- Partials     2196     3379    +1183     

Flag	Coverage Δ
unittests	76.28% <100.00%> (+0.62%)	⬆️

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: JmPotato, lhy1024

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• OWNERS [JmPotato,lhy1024]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-02-07 11:39:29.332977019 +0000 UTC m=+11011.729199076: ☑️ agreed by lhy1024.
• 2025-02-08 06:30:22.775549554 +0000 UTC m=+78865.171771614: ☑️ agreed by JmPotato.