Remove unused use-statement

tests/modules/admin/lib/Controller/ConfigTest.php

@@ -6,7 +6,6 @@ namespace SimpleSAML\Test\Module\admin\Controller;
 
 use PHPUnit\Framework\TestCase;
 use SimpleSAML\Configuration;
-use SimpleSAML\HTTP\RunnableResponse;
 use SimpleSAML\Module\admin\Controller;
 use SimpleSAML\Session;
 use SimpleSAML\Utils;