Try to close notification on all platforms which support it, not just electron

src/BasePlatform.ts

@@ -155,7 +155,13 @@ export default abstract class BasePlatform {
 
     loudNotification(ev: Event, room: Object) {
     }
+
     clearNotification(notif: Notification) {
+        // Some browsers don't support this, e.g Safari on iOS
+        // https://developer.mozilla.org/en-US/docs/Web/API/Notification/close
+        if (notif.close) {
+            notif.close();
+        }
     }
 
     /**