metrics: fix patrol panel

[lhy1024]

What problem does this PR solve?

Issue Number: Close #8115

What is changed and how does it work?

Check List

Tests

• Unit test
• Manual test (add detailed scripts or steps below)

tiup play ground with resign leader

Before

After

tiup with ms

operator with ms

Release note

None.

[ti-chi-bot[bot]]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• HuSharp
• rleungx

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 77.38%. Comparing base (a3c5950) to head (538e2f3).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8116      +/-   ##
==========================================
+ Coverage   77.35%   77.38%   +0.02%     
==========================================
  Files         471      471              
  Lines       61348    61348              
==========================================
+ Hits        47458    47473      +15     
+ Misses      10314    10306       -8     
+ Partials     3576     3569       -7     

Flag	Coverage Δ
unittests	77.38% <ø> (+0.02%)	:arrow_up:

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[lhy1024]

max(max(pd_checker_patrol_regions_time{k8s_cluster="$k8s_cluster", tidb_cluster="$tidb_cluster"})by(instance))

We try to build a case, pd_checker_patrol_regions_time in old leader is 12.7ms, pd_checker_patrol_regions_time in new leader is 10.1ms

max(max(pd_checker_patrol_regions_time{k8s_cluster="$k8s_cluster", tidb_cluster="$tidb_cluster"})by(instance)) show 10.1 ms

[lhy1024]

/merge

[ti-chi-bot[bot]]

@lhy1024: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

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[ti-chi-bot[bot]]

This pull request has been accepted and is ready to merge.

Commit hash: 538e2f33f6dc75bf0fdd37497f8b8d174ee19539

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #8152.