Bump next from 15.5.4 to 16.0.0 in /e2e/browser/test-app (#2760)

Bumps [next](https://github.com/vercel/next.js) from 15.5.4 to 16.0.0.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.5.4...v16.0.0)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 16.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Author: dependabot[bot]