FIX: don't return 200s when login is required to paths

When running `ensure_login_required` it should always happen prior to
`check_xhr` cause check xhr will trigger a 200 response

app/controllers/composer_messages_controller.rb

@@ -2,7 +2,7 @@ require_dependency 'composer_messages_finder'
 
 class ComposerMessagesController < ApplicationController
 
-  before_action :ensure_logged_in
+  prepend_before_action :check_xhr, :ensure_logged_in
 
   def index
     finder = ComposerMessagesFinder.new(current_user, params.slice(:composer_action, :topic_id, :post_id))