chore(deps): bump undici and vercel in /pages-e2e/fixtures/issue797app (

#817)

Bumps [undici](https://github.com/nodejs/undici) to 5.28.4 and updates ancestor dependency [vercel](https://github.com/vercel/vercel/tree/HEAD/packages/cli). These dependencies need to be updated together.


Updates `undici` from 5.26.5 to 5.28.4
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v5.26.5...v5.28.4)

Updates `vercel` from 34.2.4 to 34.2.8
- [Release notes](https://github.com/vercel/vercel/releases)
- [Changelog](https://github.com/vercel/vercel/blob/main/packages/cli/CHANGELOG.md)
- [Commits](https://github.com/vercel/vercel/commits/[email protected]/packages/cli)

---
updated-dependencies:
- dependency-name: undici
  dependency-type: indirect
- dependency-name: vercel
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>