Revert Vite upgrade to resolve Node.js 20.14+ compatibility and E2E test failures

- Reverted vite from ^7.0.6 back to ^5.4.18 (pre-PR #2630 version)
- Reverted @vitejs/plugin-react from ^4.7.0 back to ^4.3.3 (pre-PR #2630 version)
- Regenerated package-lock.json with compatible dependencies
- Vite 5.4.18 supports Node.js ^18.0.0 || >=20.0.0 (compatible with 20.14+)
- Build and dev server verified to work correctly with reverted versions

Co-authored-by: pamelafox <[email protected]>

Author: Copilot