SilverStripe\UserForms\Control\UserDefinedFormController::addUserFormsValidatei18n
Add the necessary jQuery validate i18n translation files, either by locale or by langauge, e.g. 'en_NZ' or 'en'. This adds "methods_abc.min.js" as well as "messages_abc.min.js" from the jQuery validate thirdparty library from dist/js.
Signature
protected function addUserFormsValidatei18n()