Fix stats redirect

When an unauthenticated user comes to any page they are redirected
to login screen. After they authenticate they are redirected
to the original page. But the # part of the url is ignored.
So we have to use regular query params from the email and
redirect user to the canonical URL later.

[MAILPOET-2554]

tests/integration/Cron/Workers/StatsNotifications/WorkerTest.php

@@ -209,7 +209,7 @@ class WorkerTest extends \MailPoetTest {
         $this->anything(),
         $this->callback(function($context){
           return strpos($context['linkSettings'], 'mailpoet-settings')
-            && strpos($context['linkStats'], 'mailpoet-newsletters#/stats');
+            && strpos($context['linkStats'], 'mailpoet-newsletters&stats');
         }));
 
     $this->statsNotifications->process();