[TASK] Replace deprecated function with doctrine query to retrieve pageroots for the backend module

Classes/Service/MailTemplateService.php

@@ -33,6 +33,7 @@ use SGalinski\SgMail\Domain\Repository\MailRepository;
 use SGalinski\SgMail\Domain\Repository\TemplateRepository;
 use Swift_Attachment;
 use Swift_OutputByteStream;
+use TYPO3\CMS\Core\Database\ConnectionPool;
 use TYPO3\CMS\Core\Mail\MailMessage;
 use TYPO3\CMS\Core\Resource\FileInterface;
 use TYPO3\CMS\Core\Resource\ResourceFactory;
@@ -515,10 +516,23 @@ class MailTemplateService {
 		}
 
 		if ($pageUid === 0) {
-			$pageRepository = $this->objectManager->get(PageRepository::class);
-			$rootPageRows = $pageRepository->getRecordsByField(
-				'pages', 'is_siteroot', 1, 'hidden = 0', '', 'sorting', 1
+			$queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)->getQueryBuilderForTable(
+				'pages'
 			);
+			$rootPageRows = $queryBuilder->select('*')
+				->from('tx_sgshop_domain_model_voucher')
+				->where(
+					$queryBuilder->expr()->eq(
+						'is_siteroot', 1
+					)
+				)
+				->andWhere(
+					$queryBuilder->expr()->eq(
+						'hidden', 0
+					)
+				)
+				->execute()->fetchAll();
+
 			if ($rootPageRows && \count($rootPageRows)) {
 				$pageUid = (int) $rootPageRows[0]['uid'];
 			}