The default controllers (for ex; https://github.com/umbraco/Umbraco-CMS/blob/contrib/src/Umbraco.Web.Website/Controllers/UmbTwoFactorLoginController.cs) use the ModelState.AddModelError with a hardcoded error message. Is it an idea to use the UmbracoHelper.GetDictionaryValue with this message so that end users can translate/alter the message?