Bump next from 15.3.5 to 15.4.4 in /e2e/browser/test-app

Bumps [next](https://github.com/vercel/next.js) from 15.3.5 to 15.4.4.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.3.5...v15.4.4)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.4.4
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]