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

- implemented CR

Author: aplapana

app/code/Magento/CatalogSearch/Test/Unit/Model/Indexer/FulltextTest.php

@@ -10,6 +10,7 @@
 use Magento\CatalogSearch\Model\Indexer\Fulltext;
 use Magento\CatalogSearch\Model\Indexer\Fulltext\Action\Full;
 use Magento\CatalogSearch\Model\Indexer\Fulltext\Action\FullFactory;
+use Magento\Elasticsearch\Model\Indexer\IndexerHandler;
 use Magento\Framework\Indexer\SaveHandler\IndexerInterface;
 use Magento\CatalogSearch\Model\Indexer\IndexerHandlerFactory;
 use Magento\CatalogSearch\Model\Indexer\Scope\State;
@@ -64,7 +65,7 @@ protected function setUp(): void
             ['create']
         );
         $fullActionFactory->expects($this->any())->method('create')->willReturn($this->fullAction);
-        $this->saveHandler = $this->getClassMock(IndexerInterface::class);
+        $this->saveHandler = $this->getClassMock(IndexerHandler::class);
         $indexerHandlerFactory = $this->createPartialMock(
             IndexerHandlerFactory::class,
             ['create']