test: make TestStoreWatch stable

[okJiang]

What problem does this PR solve?

Issue Number: Close #8692

What is changed and how does it work?

see #8692 (comment)

Check List

Tests

• Unit test
• Integration test

Release note

None.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: rleungx

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-10-16 10:09:31.037199483 +0000 UTC m=+438568.186109308: ☑️ agreed by rleungx.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.73%. Comparing base (48e72f1) to head (51f289d).
Report is 6 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8724      +/-   ##
==========================================
+ Coverage   71.70%   71.73%   +0.02%     
==========================================
  Files         517      517              
  Lines       67450    67451       +1     
==========================================
+ Hits        48364    48383      +19     
+ Misses      15521    15509      -12     
+ Partials     3565     3559       -6     

Flag	Coverage Δ
unittests	71.73% <ø> (+0.02%)	⬆️

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[ti-chi-bot]

@okJiang: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-integration-realcluster-test	51f289d	link	false	/test pull-integration-realcluster-test

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