feat: Notification on new messages in conversation (#1204)

fixes: #895
fixes: #1118
fixes: #1075

Co-authored-by: Pranav Raj S <pranav@thoughtwoot.com>

lib/integrations/facebook/delivery_status.rb

@@ -26,7 +26,7 @@ class Integrations::Facebook::DeliveryStatus
   def update_message_status
     return unless conversation
 
-    conversation.user_last_seen_at = @params.at
+    conversation.contact_last_seen_at = @params.at
     conversation.save!
   end
 end