chore: Apply rector:strict ruleset

So that CI is green again.

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

Author: come-nc

lib/private/Files/Storage/Wrapper/Wrapper.php

@@ -27,7 +27,7 @@
 use Psr\Log\LoggerInterface;
 
 class Wrapper implements Storage, ILockingStorage, IWriteStreamStorage {
-	protected ?IStorage $storage = null;
+	protected ?IStorage $storage;
 
 	public ?ICache $cache = null;