build(daffio): use the Graycore default vercel.json

This file was overwriting the default `vercel.json` used in the
Github action. https://github.com/graycoreio/github-actions/blob/main/angular-universal-vercel/vercel.json

This caused unexpected override behavior.

Now, this will just track the standard Graycore Angular Vercel workflow
structure.