Bump the dev-dependencies group across 1 directory with 2 updates

Bumps the dev-dependencies group with 2 updates in the /npm_and_yarn/helpers directory: [eslint](https://github.com/eslint/eslint) and [prettier](https://github.com/prettier/prettier).


Updates `eslint` from 9.16.0 to 9.21.0
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/main/CHANGELOG.md)
- [Commits](eslint/eslint@v9.16.0...v9.21.0)

Updates `prettier` from 3.4.2 to 3.5.2
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/main/CHANGELOG.md)
- [Commits](prettier/prettier@3.4.2...3.5.2)

---
updated-dependencies:
- dependency-name: eslint
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: dev-dependencies
- dependency-name: prettier
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: dev-dependencies
...

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