fix: doris scale in

[1aal]

• fix: https://github.com/apecloud/apecloud/issues/14751
• fix: https://github.com/apecloud/apecloud/issues/14757
• fix: https://github.com/apecloud/apecloud/issues/14768
• Currently, the number of FE nodes with the Doris follower role in KB can only be 1 or 3. Therefore, for the scale-in Ops depend on the switchover scenario, pod 0 should be specified as the only candidate node.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (0cec784) to head (5a28988).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2233   +/-   ##
=====================================
  Coverage   0.00%   0.00%           
=====================================
  Files         72      72           
  Lines       9480    9480           
=====================================
  Misses      9480    9480           

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[1aal]

/approve

[apecloud-bot]

/cherry-pick release-1.0

[apecloud-bot]

🤖 says: cherry pick action finished successfully 🎉!
See: https://github.com/apecloud/kubeblocks-addons/actions/runs/19319437780