chore(psalm): Fix or silence last psalm errors

Signed-off-by: Côme Chilliet <come.chilliet@nextcloud.com>

Author: come-nc

lib/CacheListener.php

@@ -33,7 +33,9 @@ public function onCacheEvent(ICacheEvent $event): void {
 		if (!$storage->instanceOfStorage(Jail::class)) {
 			return;
 		}
-		if ($path = $storage->getJailedPath($event->getPath())) {
+		/** @var Jail $storage */
+		$path = $storage->getJailedPath($event->getPath());
+		if ($path !== null) {
 			$event->setPath($path);
 		}
 	}

psalm.xml

@@ -130,6 +130,7 @@
 	<issueHandlers>
 		<LessSpecificReturnType errorLevel="error"/>
 		<PossiblyNullOperand errorLevel="error"/>
+		<ClassMustBeFinal errorLevel="suppress" />
 	</issueHandlers>
 	<plugins>
 		<pluginClass class="Psalm\PhpUnitPlugin\Plugin"/>