fixed typo

Signed-off-by: Spitap <dev@asdrip.fr>

Author: Spitfireap

lib/Controller/LoginController.php

@@ -942,7 +942,7 @@ public function backChannelLogout(string $providerIdentifier, string $logout_tok
 			// here we know the sid is not set so the sub is set
 			$sub = $logoutTokenPayload->sub;
 			try {
-				$oidcSessionsToKill[] = $this->sessionMapper->findSessionsBySubAndIss($sub, $iss);
+				$oidcSessionsToKill = $this->sessionMapper->findSessionsBySubAndIss($sub, $iss);
 			} catch (\OCP\Db\Exception $e) {
 				$this->logger->debug('[BackchannelLogout] Database failure while trying to retrieve user session (sub+iss)');
 			}