Fixed multiple configNode bugs

[Caideyipi]

Description

1. In Simple mode, a successful response will be returned stating "Metadata has taken effect, but WAL has not been flushed to disk." Configuration changes will be lost after a restart.
2. In the Simple mode, some files have the same sorting key, posing a risk of log replay in disorder.
3. The return TSStatus of ConsensusManager.write() is not checked, and the exception is only a warn followed by proceeding to the success branch. This means that if consensus writing is rejected, redirected, or the state machine returns a failure, the caller will still receive ACCEPT, while the local heartbeat cache/metrics have already been created in advance, leading to a divergence between metadata and runtime states.
4. The value returned by getRegionGroupCount() increases by 1 every time it is counted, and this value is used for capacity expansion judgment, display, and maxRegionGroupNum calculation, which directly affects the region scaling decision.
5. When taking a snapshot, the regionMaintainTaskList lock is not acquired before traversing. Concurrent offer/poll may throw ConcurrentModificationException or put the maintenance queue snapshot into an inconsistent state.
6. If the pipe listener fails to process the snapshot, the entire takeSnapshot() method will return false; however, ConfigRegionStateMachine combines and absorbs the failures of loadSnapshot and the pipe listener, which can amplify auxiliary link failures into consensus snapshot failures, and even mask the real failure of snapshot loading.

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This PR has:

• been self-reviewed.
  • concurrent read
  • concurrent write
  • concurrent read and write
• added documentation for new or modified features or behaviors.
• added Javadocs for most classes and all non-trivial methods.
• added or updated version, license, or notice information
• added comments explaining the "why" and the intent of the code wherever would not be obvious
  for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold
  for code coverage.
• added integration tests.
• been tested in a test IoTDB cluster.

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Key changed/added classes (or packages if there are too many classes) in this PR

[sonarqubecloud]

Quality Gate passed

Issues
7 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 32.36715% with 140 lines in your changes missing coverage. Please review.
✅ Project coverage is 40.09%. Comparing base (6042c4f) to head (2047d3a).
⚠️ Report is 5 commits behind head on master.

Files with missing lines	Patch %	Lines
...che/iotdb/confignode/manager/node/NodeManager.java	42.30%	75 Missing ⚠️
...nsensus/statemachine/ConfigRegionStateMachine.java	9.23%	59 Missing ⚠️
...gnode/persistence/executor/ConfigPlanExecutor.java	0.00%	2 Missing ⚠️
...onfignode/persistence/partition/PartitionInfo.java	71.42%	2 Missing ⚠️
...de/procedure/impl/node/AddConfigNodeProcedure.java	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #17609      +/-   ##
============================================
+ Coverage     39.94%   40.09%   +0.14%     
  Complexity     2554     2554              
============================================
  Files          5176     5176              
  Lines        348546   348658     +112     
  Branches      44564    44586      +22     
============================================
+ Hits         139242   139802     +560     
+ Misses       209304   208856     -448     

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