Fix group boards controller modules

ee/app/controllers/ee/boards/boards_controller.rb

@@ -2,6 +2,7 @@ module EE
   module Boards
     module BoardsController
       extend ActiveSupport::Concern
+
       prepended do
         before_action :check_multiple_issue_boards_available!, only: [:create]
         before_action :authorize_admin_board!, only: [:create, :update, :destroy]

ee/app/controllers/groups/boards_controller.rb

 class Groups::BoardsController < Groups::ApplicationController
-  prepend EE::Boards::BoardsController
-  prepend EE::BoardsResponses
+  prepend ::EE::Boards::BoardsController
+  prepend ::EE::BoardsResponses
   include BoardsResponses
 
   before_action :check_group_issue_boards_available!