chore: fix newly psalm errors

Author: Sysix

tests/TestClient.php

@@ -8,7 +8,6 @@
 use GuzzleHttp\Handler\MockHandler;
 use GuzzleHttp\HandlerStack;
 use GuzzleHttp\Psr7\Response;
-use Override;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 use Sysix\LexOffice\Api;