fix: retrieve all info instead of checking on demand

[WenyXu]

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What's changed and what's your intention?

RegionLeaseKeeper should retrieve all operating regions in one operation instead of checking on demand to avoid inconsistencies caused by on-demand checking.

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR does not require documentation updates.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.29%. Comparing base (20cbc03) to head (d4c97e3).
Report is 14 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3846      +/-   ##
==========================================
- Coverage   85.63%   85.29%   -0.35%     
==========================================
  Files         954      955       +1     
  Lines      163214   163323     +109     
==========================================
- Hits       139771   139304     -467     
- Misses      23443    24019     +576