feat: apply overrides to schema datasource when diffing (#5684)
Minor change to make sure we apply the config URL when diffing with a
datasource to enable https://github.com/prisma/prisma/pull/28432 to
work.
[TML-1538](https://linear.app/prisma-company/issue/TML-1538/remove-from-schema-datasource-schema-etc-from-migrate-commands)
/prisma-branch next