Create (3d_parrallel_v2.py) - Add 3D parallelism training example script

[Haziq2006]

This PR adds a new training example under examples/3D_parallel.py that demonstrates a simple training loop with distributed (DDP/TP/PP) support.

Changes included:

-Fixed invalid docstring (""" instead of """:).

-Added fallback for local_rank in non-distributed setups.

-Wrapped dist.get_rank() and dist.destroy_process_group() with if dist.is_initialized().

-Lowered num_proc in datasets.map to avoid crashes on small machines.

-Integrated optional Weights & Biases tracking (--with_tracking).

-This script is intended to help users quickly test 3D parallelism setups with Hugging Face models.

What does this PR do?

Fixes # (issue)

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