[Fix] weights update for deepseek when enabling cuda graph

[hxdtest]

Motivation

Fix weights update for deepseek when enabling cuda graph.
If model weights is updated using load_weightsafter launching engine，the address of self_attn.w_kc and self_attn.w_vc would change, which conflicts with cuda graph.

Modifications

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[merrymercy]

can @zhaochenyang20 @fzyzcjy take a look?

[zhaochenyang20]

@hxdtest could you rebase with main?

@fzyzcjy could you help to take a look?

[fzyzcjy]

LGTM, though I wonder whether we can make such param same as other params, i.e. be not-none when creating the module (I guess not trivial though).

[merrymercy]

Can you resolve the conflicts?