BUGFIX: Allow null to be returned from searchHitForNode()

As the comment says, this might return `null`

Author: kdambekalns

Classes/Eel/ElasticSearchQueryResult.php

@@ -252,7 +252,7 @@ public function getSuggestions(): array
      * @return array the Elasticsearch hit, or NULL if it does not exist.
      * @api
      */
-    public function searchHitForNode(NodeInterface $node): array
+    public function searchHitForNode(NodeInterface $node): ?array
     {
         return $this->elasticSearchQuery->getQueryBuilder()->getFullElasticSearchHitForNode($node);
     }