make LlamaModel._update_causal_mask torch compilable
Author: winglian
Pull request: yes

# What does this PR do?

This doesn't really have a performance improvement, but at least keeps torch.compile from having a graph break here.

<img width="1031" alt="Screenshot 2024-12-10 at 2 44 06 PM" src="https://github.com/user-attachments/assets/ca5198dd-0f80-4ff6-9704-a6cb587f8ca5">



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## Who can review?

@ArthurZucker 
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Comments:
Hi @winglian, this looks like a good change, but this code is inherited by many other models using `# Copied from`. You'll need to run `make fix-copies` to propagate the change to them before the CI will be green!

thanks @Rocketknight1 TIL! changes made!

cc @ArthurZucker for review - failing test seems unrelated!

@winglian took the liberty to push the required changes, as I supposed you probably were on holidays! 🎄