[FIX] pos: Too many customer display updates

Updates to the customer display were sent too often:
 - Twice when creating a new order
 - Twice when removing a payment line
 - Every time the status of a payment line with a terminal changed

closes odoo/odoo#40024

X-original-commit: b72b08cf090acd88a74e57e0e5583e0d803659c0
Signed-off-by: Quentin Lejeune (qle) <qle@odoo.com>

addons/point_of_sale/static/src/js/models.js

@@ -680,9 +680,6 @@ exports.PosModel = Backbone.Model.extend({
         var order = new exports.Order({},{pos:this});
         this.get('orders').add(order);
         this.set('selectedOrder', order);
-        if (this.config.iface_customer_facing_display) {
-            this.send_current_order_to_customer_facing_display();
-        }
         return order;
     },
     /**
@@ -2159,6 +2156,7 @@ exports.Paymentline = Backbone.Model.extend({
     set_amount: function(value){
         this.order.assert_editable();
         this.amount = round_di(parseFloat(value) || 0, this.pos.currency.decimals);
+        this.pos.send_current_order_to_customer_facing_display();
         this.trigger('change',this);
     },
     // returns the amount of money on this paymentline
@@ -2285,8 +2283,7 @@ exports.Order = Backbone.Model.extend({
         this.paymentlines.on('remove', function(){ this.save_to_db("paymentline:rem"); }, this);
 
         if (this.pos.config.iface_customer_facing_display) {
-            this.paymentlines.on('change', this.pos.send_current_order_to_customer_facing_display, this.pos);
-            // removing last paymentline does not trigger change event
+            this.paymentlines.on('add', this.pos.send_current_order_to_customer_facing_display, this.pos);
             this.paymentlines.on('remove', this.pos.send_current_order_to_customer_facing_display, this.pos);
         }