Remove reference to site customization page locale

We don't use that attribute since we added translations for this model.

app/controllers/admin/site_customization/pages_controller.rb

@@ -35,7 +35,7 @@ class Admin::SiteCustomization::PagesController < Admin::SiteCustomization::Base
   private
 
     def page_params
-      attributes = [:slug, :more_info_flag, :print_content_flag, :status, :locale]
+      attributes = [:slug, :more_info_flag, :print_content_flag, :status]
 
       params.require(:site_customization_page).permit(*attributes,
         translation_params(SiteCustomization::Page)