Remove message thread id from mcma and update scripts (#6500)

- Remove `messageThreadId` from `messageChannelMessageAssociation`
- Update thread merging
- Update all queries which were dependent on this field
- Update some raw queries by using `twentyORM` instead

---------

Co-authored-by: Weiko <corentin@twenty.com>

packages/twenty-server/src/modules/messaging/common/standard-objects/message.workspace-entity.ts

@@ -80,7 +80,7 @@ export class MessageWorkspaceEntity extends BaseWorkspaceEntity {
     icon: 'IconCalendar',
   })
   @WorkspaceIsNullable()
-  receivedAt: string | null;
+  receivedAt: Date | null;
 
   @WorkspaceRelation({
     standardId: MESSAGE_STANDARD_FIELD_IDS.messageThread,