[TASK] Fixing wrong function name for getter

Classes/Service/MailTemplateService.php

@@ -427,7 +427,7 @@ class MailTemplateService {
 		/** @var Mail $mailToSend */
 		$mailToSend = $mailRepository->findOneByUid($uid);
 
-		if ($mailToSend && !$mailToSend->isBlacklisted()) {
+		if ($mailToSend && !$mailToSend->getBlacklisted()) {
 			$this->mailMessage->setBody($mailToSend->getMailBody(), 'text/html');
 			$this->mailMessage->setTo(trim($mailToSend->getToAddress()));
 			$this->mailMessage->setFrom($mailToSend->getFromAddress(), $mailToSend->getFromName());