Add SettingsController cache reset to integration tests

[MAILPOET-1757]

tests/integration/Router/Endpoints/TrackTest.php

@@ -13,6 +13,7 @@ use MailPoet\Tasks\Sending as SendingTask;
 
 class TrackTest extends \MailPoetTest {
   function _before() {
+    parent::_before();
     // create newsletter
     $newsletter = Newsletter::create();
     $newsletter->type = 'type';