fix: DataNode might OOM by estimating based on MemorySize

[XuanYang-cn]

See also: #34136
pr: #34201

[mergify]

@XuanYang-cn E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[XuanYang-cn]

rerun ut

[codecov]

Codecov Report

Attention: Patch coverage is 94.11765% with 2 lines in your changes missing coverage. Please review.

Project coverage is 72.53%. Comparing base (fc6bd38) to head (26b2dfd).
Report is 18 commits behind head on 2.4.

Additional details and impacted files

@@            Coverage Diff             @@
##              2.4   #34203      +/-   ##
==========================================
- Coverage   81.82%   72.53%   -9.30%     
==========================================
  Files        1010     1010              
  Lines      130787   130968     +181     
==========================================
- Hits       107021    94999   -12022     
- Misses      19766    31959   +12193     
- Partials     4000     4010      +10     

Files	Coverage Δ
pkg/util/paramtable/component_param.go	98.38% <100.00%> (+<0.01%)	⬆️
internal/datanode/compaction/l0_compactor.go	91.86% <92.59%> (-0.73%)	⬇️

... and 226 files with indirect coverage changes

[tedxu]

/lgtm

[congqixia]

/approve

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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