fix(analytics): redirect to mp3 file even when referer was not set

app/Libraries/Analytics/Controllers/EpisodeAnalyticsController.php

@@ -58,7 +58,7 @@ class EpisodeAnalyticsController extends Controller
             $serviceName = $_GET['_from'];
         } elseif ($session->get('embeddable_player_domain') !== null) {
             $serviceName = $session->get('embeddable_player_domain');
-        } elseif ($session->get('referer') !== '- Direct -') {
+        } elseif ($session->get('referer') !== null && $session->get('referer') !== '- Direct -') {
             $serviceName = parse_url($session->get('referer'), PHP_URL_HOST);
         }