Refactor database migrations and schema for Chat and Setting tables

- Removed the unique constraint on `remoteJid` and `instanceId` in the `Chat` model to prevent potential migration failures due to existing duplicates.
- Deleted the old migration file for adding `wavoipToken` to the `Setting` table and created a new migration that includes a check for the column's existence before adding it, ensuring smoother migration processes.
- Updated migration logic to clear previous migrations related to `wavoip_token` to maintain a clean migration history.

prisma/postgresql-schema.prisma

@@ -127,7 +127,6 @@ model Chat {
   unreadMessages Int       @default(0)
   @@index([instanceId])
   @@index([remoteJid])
-  @@unique([remoteJid, instanceId])
 }
 
 model Contact {