Bump prettier from 3.3.3 to 3.4.1 in /backend

Bumps [prettier](https://github.com/prettier/prettier) from 3.3.3 to 3.4.1.
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/main/CHANGELOG.md)
- [Commits](prettier/prettier@3.3.3...3.4.1)

---
updated-dependencies:
- dependency-name: prettier
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>