Support passing flash_attn_kwargs when gradient_checkpointing is enabled
Author: efsotr
Pull request: yes
Labels: name: Flash Attention

# What does this PR do?

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Fixes #35509


## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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- [ ] Did you write any new necessary tests?


## Who can review?

@ArthurZucker @Rocketknight1

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