FabricModule: wrap forward methods instead of monkeypatch-based redirect

[tonyf]

What does this PR do?

When running with torch.compile and ModelParallelStrategy the monkeypatch method of redirecting forward methods through the FabricModule's custom forward method raises an exception if the marked method does not have the same signature as the original forward method.

Instead of monkeypatching forward to the method being called, this PR wraps the function to ensure the right strategy contexts are provided.

This could be cleaned up further by just wrapping the functions in mark_forward_method but that would require touching _LIGHTNING_MODULE_STEP_METHODS = ("training_step", "validation_step", "test_step", "predict_step").

Fixes #20710

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📚 Documentation preview 📚: https://pytorch-lightning--20711.org.readthedocs.build/en/20711/

[Borda]

seems the falling stand-alone test is a false alarm :)
but the others seems real...

[codecov]

Codecov Report

Attention: Patch coverage is 8.33333% with 11 lines in your changes missing coverage. Please review.

Project coverage is 79%. Comparing base (4281b58) to head (0798ef7).
Report is 1 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (4281b58) and HEAD (0798ef7). Click for more details.

HEAD has 1086 uploads less than BASE

Flag	BASE (4281b58)	HEAD (0798ef7)
cpu	270	27
python	30	3
lightning_fabric	63	2
pytest	139	2
python3.10	60	6
python3.12.7	90	9
lightning	151	15
python3.11	60	6
python3.12	30	3
gpu	4	2
pytorch2.1	30	6
pytorch_lightning	60	12
pytest-full	135	27
pytorch2.2.2	15	3
pytorch2.5	15	3
pytorch2.3	15	3
pytorch2.4.1	15	3
pytorch2.5.1	15	3
pytorch2.6	15	3
pytorch2.7	15	3

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #20711     +/-   ##
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- Coverage      87%      79%     -8%     
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  Files         268      268             
  Lines       23449    23449             
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- Hits        20389    18472   -1917     
- Misses       3060     4977   +1917     

[tonyf]

Ah! looks like I need to update the redirection tests. Will try to get around to it soon. Currently using this fix in prod successfully