chore(deps): bump zod and next in /examples/nextjs

Removes [zod](https://github.com/colinhacks/zod). It's no longer used after updating ancestor dependency [next](https://github.com/vercel/next.js). These dependencies need to be updated together.


Removes `zod`

Updates `next` from 13.4.10 to 13.5.4
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v13.4.10...v13.5.4)

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

Signed-off-by: dependabot[bot] <support@github.com>