Make ApplicationData a plain module include

app/models/clusters/concerns/application_data.rb

@@ -3,9 +3,6 @@
 module Clusters
   module Concerns
     module ApplicationData
-      extend ActiveSupport::Concern
-
-      included do
       def uninstall_command
         Gitlab::Kubernetes::Helm::DeleteCommand.new(
           name: name,
@@ -55,5 +52,4 @@ module Clusters
       end
     end
   end
-  end
 end