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/User/user.schema.ts

@@ -1,6 +1,6 @@
 import { clerkClient } from '@clerk/express'
 import { Inject, Injectable, Logger } from '@nestjs/common'
-import { ChatRoom, Message, MessageContextType, MessageType, Role } from '@prisma/client'
+import { Message, Role } from '@prisma/client'
 import { Pothos, PothosRef, PothosSchema, SchemaBuilderToken } from '@smatch-corp/nestjs-pothos'
 import { ChatroomSchema } from '../ChatRoom/chatroom.schema'
 import { Builder, SchemaContext } from '../Graphql/graphql.builder'
@@ -547,17 +547,15 @@ export class UserSchema extends PothosSchema {
     this.builder.subscriptionFields((t) => ({
       userScopedMessage: t.field({
         type: this.messageSchema.message(),
-        subscribe: async (_, _args, ctx: SchemaContext) => {
+        subscribe: async (_, _args, ctx) => {
           if (!ctx.isSubscription) {
             throw new Error('Not allowed')
           }
-          const {
-            websocket: { pubSub },
-          } = ctx
-          return pubSub.asyncIterableIterator([
+
+          return ctx.websocket.pubSub.asyncIterator([
             `${PubSubEvent.NEW_MESSAGE}.${ctx.websocket.me?.id}`,
             `${PubSubEvent.NOTIFICATION}.${ctx.websocket.me?.id}`,
-          ])
+          ]) as unknown as AsyncIterable<Message>
         },
         resolve: async (payload: Message) => payload,
       }),