[FIX] point_of_sale: barcode and ENTER key

- Set a barcode for a product A
- Open the POS interface
- Click on a product B => it is added to the order
- Scan product A

Product A is added to the order, but a unit of B is also added.

Commit 9de1bc0eef introduced keyboard shortcuts in the POS
interface. In particular, when a product is selected, pressing the SPACE
or the ENTER key adds it in the order. Since the barcode scanner sends
an ENTER key as a final character, it triggers the addition of both
products.

opw-1934520

closes odoo/odoo#31185

addons/point_of_sale/static/src/js/screens.js

@@ -842,8 +842,8 @@ var ProductListWidget = PosBaseWidget.extend({
         };
 
         this.keypress_product_handler = function(ev){
-            if (ev.which != 13 && ev.which != 32) {
-                // Key is not space or enter
+            // React only to SPACE to avoid interfering with warcode scanner which sends ENTER
+            if (ev.which != 32) {
                 return;
             }
             ev.preventDefault();