Prevent statistics from being loaded outside of admin

closes flarum/core#1311

extensions/statistics/src/Listener/AddStatisticsData.php

@@ -49,11 +49,13 @@ class AddStatisticsData
      */
     public function addStatisticsData(ConfigureWebApp $event)
     {
+        if ($event->isAdmin()) {
             $event->view->setVariable('statistics', array_merge(
                 $this->getStatistics(),
-            ['utcOffset' => $this->getUTCOffset()]
+                ['timezoneOffset' => $this->getUserTimezone()->getOffset(new DateTime)]
             ));
         }
+    }
 
     private function getStatistics()
     {