Fix batch number

[XianzheMa]

Previously, we didn't record the number of passed batches correctly:
We use a batch_number which is generated purely from enumeration in dataloader. Therefore this number is irrelevant to the number of epochs (only shows how many batches there are in one epoch).
A similar issue exists on the iteration on StB when we calculate scores class by class. The number of batches passed in the previous class is not correctly accumulated on the current class.

This PR fixes it.

[github-actions]

^{( % to main)
( % to main)}

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 3 lines in your changes missing coverage. Please review.

Project coverage is 82.81%. Comparing base (bf96bfa) to head (9b2a8c9).
Report is 1 commits behind head on main.

❗ Current head 9b2a8c9 differs from pull request most recent head 07ebc07

Please upload reports for the commit 07ebc07 to get more accurate results.

Files	Patch %	Lines
...trainer_server/internal/trainer/pytorch_trainer.py	82.35%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #533      +/-   ##
==========================================
+ Coverage   82.31%   82.81%   +0.50%     
==========================================
  Files         217      217              
  Lines       10125    10124       -1     
==========================================
+ Hits         8334     8384      +50     
+ Misses       1791     1740      -51     

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[MaxiBoether]

Thanks for catching this. My only comment is whether we should log both numbers :)