Replace notify method by binded version in constructor of chat and notification menu

We need to keep a reference to the binded method registered to be able to
unregister it.

Closes #14425

sao/src/chat.js

@@ -5,8 +5,9 @@
 
     class _Chat {
         constructor(record) {
+            this.notify = this.notify.bind(this);
             this.record = record;
-            Sao.Bus.register(`chat:${this.record}`, this.notify.bind(this));
+            Sao.Bus.register(`chat:${this.record}`, this.notify);
             this.el = this.__build();
         }
 

sao/src/notification.js

@@ -6,6 +6,7 @@
 
     class _NotificationMenu {
         constructor() {
+            this.notify = this.notify.bind(this);
             this.el = jQuery('<ul/>', {
                 'class': 'notification-menu dropdown-menu',
                 'role': 'menu',

sao/src/sao.js

@@ -614,8 +614,7 @@ var Sao = {
                                 let user_id = Sao.Session.current_session.user_id;
                                 Sao.Bus.register(
                                     `notification:${user_id}`,
-                                    Sao.NotificationMenu.notify
-                                    .bind(Sao.NotificationMenu));
+                                    Sao.NotificationMenu.notify);
                                 Sao.NotificationMenu.count();
                                 Sao.Bus.listen();
 
@@ -642,7 +641,7 @@ var Sao = {
             jQuery('#menu').empty();
             let user_id = Sao.Session.current_session.user_id;
             Sao.Bus.unregister(
-                `notification:${user_id}`, Sao.NotificationMenu.update);
+                `notification:${user_id}`, Sao.NotificationMenu.notify);
             session.do_logout().always(Sao.login);
             Sao.set_title();
         });