Packing Report: Refactor view to be reusable by other reports

For now this view is used only in the context of packing, but later we would move all existing rpeort to use same view

app/controllers/admin/reports_controller.rb

@@ -30,7 +30,7 @@ module Admin
       assign_view_data
       load_form_options
 
-      render report_type
+      render "show"
     end
 
     def assign_view_data
@@ -39,6 +39,9 @@ module Admin
       @report_subtypes = report_class.report_subtypes.map do |subtype|
         [t("packing.#{subtype}_report", scope: i18n_scope), subtype]
       end
+      if @report_type == "packing"
+        @report_message = I18n.t("spree.admin.reports.customer_names_message.customer_names_tip")
+      end
     end
 
     def load_form_options