message: fix json field being set to empty string
diff: @@ -113,6 +113,10 @@ const getInitialValues = (fields: Fields): Values =>
  value = 0;
  break;
  + case FieldType.json:
  + value = {};
  + break;
  +
  case FieldType.shortText:
  case FieldType.longText:
  case FieldType.email:
  