CRM-8025: Consumer is being interrupted with "Invalid filters structu…

…re" error (#9107)

- remove data-validation-optional
 - check empty filters in FilterProcessor

src/Oro/Bundle/QueryDesignerBundle/QueryDesigner/FilterProcessor.php

@@ -42,6 +42,7 @@ public function filter(QueryBuilder $queryBuilder, WidgetOptionBag $widgetOption
      */
     public function process(QueryBuilder $qb, $rootEntity, array $filters, $rootEntityAlias)
     {
+        $filters = array_filter($filters);
         if (!$filters) {
             // nothing to do
             return $qb;