fix(renderer): Ignore empty values in length validators

Author: rvsia

packages/react-form-renderer/src/validators/index.js

@@ -21,7 +21,11 @@ export const length = memoize(({
   equal = selectNum(equal, is);
   min = selectNum(min, minimum);
   max = selectNum(max, maximum);
-  return prepare ((value = []) => {
+  return prepare ((value) => {
+    if (!value) {
+      return;
+    }
+
     if (equal !== null && value.length !== equal) {
       const msg = prepareMsg(message, 'wrongLength', { count: equal }).defaultMessage;
       return typeof msg === 'string' ? msg : msg(equal);