Use configured validation classes in React Vanilla Radio Group

The React Vanilla Radio Group now uses the configured validation
CSS classes, similar to other controls like the InputControl, instead
of hard coding them.

Author: andresgutgon

packages/vanilla/src/controls/RadioGroup.tsx

@@ -58,7 +58,9 @@ export const RadioGroup = ({
   const radioInput = useMemo(() => findStyleAsClassName(contextStyles)('control.radio.input'), [contextStyles]);
   const radioLabel = useMemo(() => findStyleAsClassName(contextStyles)('control.radio.label'), [contextStyles]);
   const isValid = errors.length === 0;
-  const divClassNames = `validation  ${isValid ? classNames.description : 'validation_error' }`;
+  const divClassNames = [classNames.validation]
+    .concat(isValid ? classNames.description : classNames.validationError)
+    .join(' ');
   const appliedUiSchemaOptions = merge({}, config, uischema.options);
   const showDescription = !isDescriptionHidden(
     visible,