chore(deps-dev): bump vite in /demos/using-dev-build

Bumps [vite](https://github.com/vitejs/vite/tree/HEAD/packages/vite) from 5.4.21 to 6.4.2.
- [Release notes](https://github.com/vitejs/vite/releases)
- [Changelog](https://github.com/vitejs/vite/blob/v6.4.2/packages/vite/CHANGELOG.md)
- [Commits](https://github.com/vitejs/vite/commits/v6.4.2/packages/vite)

---
updated-dependencies:
- dependency-name: vite
  dependency-version: 6.4.2
  dependency-type: direct:development
...

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Author: dependabot[bot]