fix(schema.prisma): Remove shadowDatabaseUrl

`shadowDatabaseUrl` is no longer required for Vercel Postgres and may cause issues when set to the same value as `directUrl`

Author: ruheni

prisma/schema.prisma

@@ -2,7 +2,6 @@ datasource db {
   provider = "postgresql"
   url = env("POSTGRES_PRISMA_URL") // uses connection pooling
   directUrl = env("POSTGRES_URL_NON_POOLING") // uses a direct connection
-  shadowDatabaseUrl = env("POSTGRES_URL_NON_POOLING") // used for migrations
 }
 
 generator client {
@@ -52,4 +51,4 @@ model VerificationToken {
   expires    DateTime
 
   @@unique([identifier, token])
-}
+}