build(deps-dev): bump @nx/next from 18.3.4 to 19.4.3

Bumps [@nx/next](https://github.com/nrwl/nx/tree/HEAD/packages/next) from 18.3.4 to 19.4.3.
- [Release notes](https://github.com/nrwl/nx/releases)
- [Commits](https://github.com/nrwl/nx/commits/19.4.3/packages/next)

---
updated-dependencies:
- dependency-name: "@nx/next"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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