Remove shadowDatabaseUrl from Prisma now That Vercel Improved Migrations Handling

[MarioGiancini]

Overview

When doing a second migration with prisma, you are presented with Error: P3005:

Error: P3005

The database schema is not empty. Read more about how to baseline an existing production database: https://pris.ly/d/migrate-baseline

Removing the shadowDatabaseUrl from the schema.prisma datasource fixes this.

With latest updates from Vercel, we no longer need the shadowDatabaseUrl to handle migrations.

See: prisma/prisma#19234 (comment)