Bump next from 13.4.7 to 14.2.21 in /example/web-next-transformstream

Bumps [next](https://github.com/vercel/next.js) from 13.4.7 to 14.2.21.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v13.4.7...v14.2.21)

---
updated-dependencies:
- dependency-name: next
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]