ACP2E-1875: [Magento Cloud] Products incorrectly showed Out of Stock then all products show in stock

- addressed missing doc issue

Author: aplapana

app/code/Magento/Elasticsearch/Model/Indexer/IndexerHandler.php

@@ -181,7 +181,9 @@ public function deleteIndex($dimensions, \Traversable $documents)
         $scopeId = $this->scopeResolver->getScope($dimension->getValue())->getId();
         $documentIds = [];
         foreach ($documents as $document) {
-            $documentIds[$document] = $document;
+            if ($document) {
+                $documentIds[$document] = $document;
+            }
         }
         $this->adapter->deleteDocs($documentIds, $scopeId, $this->getIndexerId());
         return $this;