feat: setting Auto-Submitted for notification mails

uses method from nextcloud/server#35876

Signed-off-by: Bennet Becker <dev@bennet.cc>

lib/MailQueueHandler.php

@@ -35,6 +35,7 @@
 use OCP\IUser;
 use OCP\IUserManager;
 use OCP\L10N\IFactory;
+use OCP\Mail\Headers\AutoSubmitted;
 use OCP\Mail\IMailer;
 use OCP\RichObjectStrings\InvalidObjectExeption;
 use OCP\RichObjectStrings\IValidator;
@@ -375,6 +376,9 @@ protected function sendEmailToUser($userName, $email, $lang, $timezone, $maxTime
 		$message->useTemplate($template);
 		$message->setFrom([$this->getSenderData('email') => $this->getSenderData('name')]);
 
+		// We don't want auto generated responses to autogenerated activity notifications
+		$message->setAutoSubmitted(AutoSubmitted::VALUE_AUTO_GENERATED);
+
 		try {
 			$this->mailer->send($message);
 		} catch (\Exception $e) {