nightly-2024-09-24: feat: swap endianness in-place in keccak implementation (#6128)

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

This PR removes the `temp` array created when swapping the endianness of
the `block_bytes` array and just swaps the values in place. This removes
some unnecessary reads/writes from brillig.

## Additional Context



## Documentation\*

Check one:
- [x] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[For Experimental Features]** Documentation to be submitted in a
separate PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.