deps: bump curve25519-dalek (#2382)

## Description

Fixes `cargo-deny` warning for
[RUSTSEC-2024-0344](https://rustsec.org/advisories/RUSTSEC-2024-0344):

*Timing variability in `curve25519-dalek`'s
`Scalar29::sub`/`Scalar52::sub`*

Upstream PR:
dalek-cryptography/curve25519-dalek#659

## Breaking Changes

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including how to migrate older code. -->

## Notes & open questions

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## Change checklist

- [x] Self-review.
- [ ] ~~Documentation updates if relevant.~~
- [ ] ~~Tests if relevant.~~
- [x] All breaking changes documented.

Author: Frando