fix(tikv): fix unexpected hangs (#6459)

[ti-chi-bot]

This is an automated cherry-pick of #6459

• tso group breaks because feature gates are not synced. The cluster controller should watch tso group changes.
• use a more stable way to check whether a tikv instance should requeue because the pod is ready but not available.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 6.66667% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 45.32%. Comparing base (f7a70d1) to head (ab7618d).

Additional details and impacted files

@@               Coverage Diff               @@
##           release-2.0    #6460      +/-   ##
===============================================
- Coverage        45.35%   45.32%   -0.03%     
===============================================
  Files              309      309              
  Lines            20769    20755      -14     
===============================================
- Hits              9420     9408      -12     
+ Misses           11349    11347       -2     

Flag	Coverage Δ
unittest	45.32% <6.66%> (-0.03%)	⬇️

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[liubog2008]

/lgtm

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-09-22 02:23:47.733066157 +0000 UTC m=+237037.803559833: ☑️ agreed by liubog2008.

[ti-chi-bot]

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This pull-request has been approved by: liubog2008

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