Remove new message audio notification

Bye, bye, dear Ka-Klunk!

js/notifications.js

@@ -14,7 +14,6 @@
     };
 
     let isEnabled = false;
-    var sound = new Audio('audio/NewMessage.mp3');
 
     Whisper.Notifications = new (Backbone.Collection.extend({
         initialize: function() {
@@ -48,11 +47,6 @@
                 return;
             }
 
-            var audioNotification = storage.get('audio-notification') || false;
-            if (audioNotification) {
-                sound.play();
-            }
-
             var setting = storage.get('notification-setting') || 'message';
             if (setting === SETTINGS.OFF) {
                 return;