update weight update process group

[ji-huazhong]

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Fixes # (issue)

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[jiangix-paper]

Hello, can i use it to do trl grpo in npu?
this is my question:
vllm-project/vllm-ascend#459

[ji-huazhong]

@jiangix-paper
The current draft uses torch's collective communication interface, and some problems were found during testing, such as not supporting multi-NPU training. To solve this problem, I plan to refer to the existing implementation and introduce PyNcclCommunicator to support the creation of weight communication groups.