maxLength static method
Check if the string has max max chars
if string is not null and not empty.
Returns null if is valid.
Returns FieldBlocValidatorsErrors.maxLength if is not valid. Max length validator.
Implementation
static Validator<String?> maxLength(int max, {String? errorMessage}) {
  return (String? string) {
    if (string == null || string.isEmpty || string.length <= max) {
      return null;
    }
    return errorMessage ?? FieldBlocValidatorsErrors.maxLength;
  };
}