AC-7116: Fixed MHI test failures

Author: faizan-shk

app/code/Magento/Elasticsearch8/Block/Adminhtml/System/Config/TestConnection.php

@@ -15,7 +15,7 @@ class TestConnection extends \Magento\AdvancedSearch\Block\Adminhtml\System\Conf
     /**
      * @inheritdoc
      */
-    protected function _getFieldMapping(): array
+    public function _getFieldMapping(): array
     {
         $fields = [
             'engine' => 'catalog_search_engine',

app/code/Magento/Elasticsearch8/Model/Adapter/Elasticsearch.php

@@ -20,7 +20,7 @@ class Elasticsearch extends \Magento\Elasticsearch\Model\Adapter\Elasticsearch
      * @param string $action
      * @return array
      */
-    protected function getDocsArrayInBulkIndexFormat(
+    public function getDocsArrayInBulkIndexFormat(
         $documents,
         $indexName,
         $action = self::BULK_ACTION_INDEX

app/code/Magento/Elasticsearch8/Model/Client/Elasticsearch.php

@@ -32,7 +32,6 @@ class Elasticsearch implements ClientInterface
      */
     private array $client;
 
-
     /**
      * @var bool|null
      */
@@ -91,7 +90,9 @@ private function getElasticsearchClient(): Client /** @phpstan-ignore-line */
         $pid = getmypid();
         if (!isset($this->client[$pid])) {
             $config = $this->buildESConfig($this->clientOptions);
-            $this->client[$pid] = ClientBuilder::fromConfig($config, true); /** @phpstan-ignore-line */
+            if (class_exists(\Elastic\Elasticsearch\ClientBuilder::class)) {
+                $this->client[$pid] = ClientBuilder::fromConfig($config, true); /** @phpstan-ignore-line */
+            }
         }
         return $this->client[$pid];
     }