cluster: fix store state change problem (#9257)

[ti-chi-bot]

This is an automated cherry-pick of #9257

What problem does this PR solve?

Issue Number: Close #8997

What is changed and how does it work?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below) TestConcurrentStoreStats will fail in master

--- FAIL: TestConcurrentStoreStats (0.02s)
    /home/lhy1024/pd/server/cluster/cluster_test.go:3893: 
          Error Trace:  /home/lhy1024/pd/server/cluster/cluster_test.go:3893
          Error:        Not equal: 
                        expected: 2
                        actual  : 1
          Test:         TestConcurrentStoreStats
          Messages:     store 1 should be in removing state
[2025/04/24 18:44:44.368 +08:00] [INFO] [cluster.go:1698] ["store has changed to serving"] [store-id=6] [store-address=127.0.0.1:6]
FAIL
[2025/04/24 18:44:44.368 +08:00] [INFO] [cluster.go:1698] ["store has changed to serving"] [store-id=9] [store-address=127.0.0.1:9]
FAIL  github.com/tikv/pd/server/cluster  0.191s
FAIL

Release note

None.

[ti-chi-bot]

@lhy1024 This PR has conflicts, I have hold it. Please resolve them or ask others to resolve them, then comment /unhold to remove the hold label.

[ti-chi-bot[bot]]

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[codecov[bot]]

Codecov Report

:x: Patch coverage is 76.19048% with 20 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 77.70%. Comparing base (ee6c8cf) to head (a6a8719). :warning: Report is 3 commits behind head on release-8.5.

Additional details and impacted files

@@               Coverage Diff               @@
##           release-8.5    #9543      +/-   ##
===============================================
+ Coverage        77.68%   77.70%   +0.01%     
===============================================
  Files              467      467              
  Lines            62369    62494     +125     
===============================================
+ Hits             48453    48559     +106     
+ Misses           10350    10347       -3     
- Partials          3566     3588      +22     

Flag	Coverage Δ
unittests	77.70% <76.19%> (+0.01%)	:arrow_up:

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[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

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

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[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2025-09-18 06:59:25.23646468 +0000 UTC m=+83126.715045337: :ballot_box_with_check: agreed by bufferflies.
• 2025-09-19 06:19:59.094751617 +0000 UTC m=+167160.573332294: :ballot_box_with_check: agreed by lhy1024.