Bump candle-flash-attn from be4f920 to bffa5e1

Bumps [candle-flash-attn](https://github.com/huggingface/candle) from `be4f920` to `bffa5e1`.
- [Commits](huggingface/candle@be4f920...bffa5e1)

---
updated-dependencies:
- dependency-name: candle-flash-attn
  dependency-version: bffa5e1a561839b9ad7eac5a4e0f969c1d8fff39
  dependency-type: direct:production
...

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Author: dependabot[bot]