chore: refactor pub/sub iterator usage across schema files

- Updated pub/sub iterator methods from `asyncIterableIterator` to `asyncIterator` in multiple schema files for improved compatibility with the latest GraphQL subscriptions.
- Refactored subscription logic in CollaborationSession, Document, Message, User, and other schema files to enhance readability and maintainability.
- Adjusted imports in GraphQL builder to utilize RedisPubSub for better performance in subscription handling.

src/Message/message.schema.ts

@@ -197,10 +197,9 @@ export class MessageSchema extends PothosSchema {
           if (!ctx.isSubscription) {
             throw new Error('Not allowed')
           }
-          const {
-            websocket: { pubSub },
-          } = ctx
-          return pubSub.asyncIterableIterator([`${PubSubEvent.MESSAGE_SENT}.${args.chatRoomId}`])
+          return ctx.websocket.pubSub.asyncIterator([
+            `${PubSubEvent.MESSAGE_SENT}.${args.chatRoomId}`,
+          ]) as unknown as AsyncIterable<Message>
         },
         resolve: (payload: Message) => payload,
       }),