Update schema.prisma

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

prisma/schema.prisma

@@ -7,7 +7,6 @@ datasource db {
   provider          = "postgresql"
   url               = env("DATABASE_URL")
   directUrl         = env("POSTGRES_URL_NON_POOLING")
-  shadowDatabaseUrl = env("POSTGRES_URL_NON_POOLING")
 }
 
 model hits {