fix bug in create user notif

src/modules/notifications/services/notification.service.ts

@@ -85,6 +85,7 @@ export class NotificationService {
       return this.em.create(Notification, {
         restaurant: param.restaurantId,
         admin: param.adminId,
+        user: param.userId && param.userId.trim() !== '' ? param.userId : null,
         title: param.title,
         content: param.content,
       });