[To rc/1.3.3] Active Load: Add metrics for file size and refactor the code (#13329)

[SteveYurongSu]

Co-authored-by: Steve Yurong Su rong@apache.org
(cherry picked from commit c5b8a59)

[sonarqubecloud]

Quality Gate passed

Issues
2 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 SonarCloud

[codecov]

Codecov Report

Attention: Patch coverage is 34.66667% with 98 lines in your changes missing coverage. Please review.

Project coverage is 41.46%. Comparing base (84a6c27) to head (1b439b1).
Report is 3 commits behind head on rc/1.3.3.

Files with missing lines	Patch %	Lines
...ine/load/metrics/ActiveLoadingFilesMetricsSet.java	33.33%	40 Missing ⚠️
...ad/metrics/ActiveLoadingFilesNumberMetricsSet.java	16.21%	31 Missing ⚠️
...load/metrics/ActiveLoadingFilesSizeMetricsSet.java	15.38%	11 Missing ⚠️
...torageengine/load/active/ActiveLoadDirScanner.java	77.27%	5 Missing ⚠️
...rageengine/load/active/ActiveLoadTsFileLoader.java	50.00%	5 Missing ⚠️
...rageengine/load/active/ActiveLoadPendingQueue.java	0.00%	4 Missing ⚠️
...otdb/db/service/metrics/DataNodeMetricsHelper.java	0.00%	2 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff               @@
##             rc/1.3.3   #13358      +/-   ##
==============================================
- Coverage       41.48%   41.46%   -0.02%     
  Complexity         71       71              
==============================================
  Files            3434     3436       +2     
  Lines          218678   218777      +99     
  Branches        26010    26013       +3     
==============================================
+ Hits            90708    90725      +17     
- Misses         127970   128052      +82     

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