build(deps): bump cacheable-request and vercel in /example/nextjs

Removes [cacheable-request](https://github.com/jaredwray/cacheable-request). It's no longer used after updating ancestor dependency [vercel](https://github.com/vercel/vercel/tree/HEAD/packages/cli). These dependencies need to be updated together.


Removes `cacheable-request`

Updates `vercel` from 25.0.1 to 28.15.3
- [Release notes](https://github.com/vercel/vercel/releases)
- [Commits](https://github.com/vercel/vercel/commits/vercel@28.15.3/packages/cli)

---
updated-dependencies:
- dependency-name: cacheable-request
  dependency-type: indirect
- dependency-name: vercel
  dependency-type: direct:production
...

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