Bump candle-flash-attn from be4f920 to df618f8

Bumps [candle-flash-attn](https://github.com/huggingface/candle) from `be4f920` to `df618f8`.
- [Commits](huggingface/candle@be4f920...df618f8)

---
updated-dependencies:
- dependency-name: candle-flash-attn
  dependency-version: df618f80083d6f95de44a2cf52044543fe79301b
  dependency-type: direct:production
...

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Author: dependabot[bot]