[Main] fix cg missing wgrad hook

[Wohox]

What does this PR do ?

This PR fixes the missing backward post hook bug, this bug happens when delay_wgrad_compute and cuda_graph are both enabled, the parameters within delayed wgrad computation scope will skip the backward post hook.

The fix is in TE, this PR only adds version guard and several flag assertions.
Related TE PR: NVIDIA/TransformerEngine#2614
PR for dev: #2999

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[Wohox]

@jiemingz Can you take a look at this PR, thanks~

[jiemingz]

LGTM; could you move this to transformer_config? I think we're trying to keep the arguments.py minimal

[Wohox]

I am afraid not, since TransformerConfig cannot access overlap_grad_reduce, which is DDPConfig

[gautham-kollu]

[Plug/FYI] Megatron-bridge has a validate() for all the configs together.
https://github.com/NVIDIA-NeMo/Megatron-Bridge/blob/main/src/megatron/bridge/training/config.py#L1399-L1661

We are trying to upstream to megatron-lm, this should help cross-config object validations.

[ericharper]

@gautham-kollu , will Bridge need the same fix?

[gautham-kollu]

@gautham-kollu , will Bridge need the same fix?

Yes. We need to upstream this to the ConfigContainer.Validate(). Filed this to track NVIDIA-NeMo/Megatron-Bridge#2216

[gautham-kollu]

/ok to test 5973386

[Phlip79]

/ok to test 8553313