[BugFix] Fix parameter names and process_after_weight_loading for W4A16 MoE Group Act Order

[dsikka]

Summary

• Fix parameter names to ensure proper weight loading
• Fix process_after_weight_loading if running group act order
• Don't shard w2 weight_scales when running actorder for tp>1

Testing

• Tested with tp>=1 with mixtral and deepseek WNA16

Next Steps:

• GPTQMarlin MoE method likely needs to be updated on its sharding condition for actorder

[github-actions]

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[eldarkurtic]

I can confirm it works with tp>1

[dsikka]

@mgoin
@robertgshaw2-neuralmagic
@ElizaWszola

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @dsikka.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[ElizaWszola]

nit: maybe rename intermediate_size -> intermediate_size_per_partition and intermediate_full -> intermediate_size?
This would make the names consistent with other quant configs, e.g. vllm/model_executor/layers/quantization/gptq.py