Feat: make __getattr__ and __setattr__ of ClasswiseWrapper more general

[daniel-code]

What does this PR do?

Fixes #2389

Related PR: #2390

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📚 Documentation preview 📚: https://torchmetrics--2424.org.readthedocs.build/en/2424/

[daniel-code]

Dear @Borda and @SkafteNicki,

This PR makes __getattr__ and __setattr__ of ClasswiseWrapper more general to fetch the attributes of inner metric and ClasswiseWrapper.

[codecov]

Codecov Report

Merging #2424 (e14c59c) into master (1951a06) will decrease coverage by 34%.
The diff coverage is 0%.

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #2424     +/-   ##
========================================
- Coverage      69%     35%    -34%     
========================================
  Files         307     307             
  Lines       17363   17363             
========================================
- Hits        11961    6050   -5911     
- Misses       5402   11313   +5911