[FIX] hw_screen: Mixed Content when loading with https

The protocol is hardcoded to `http` in the url for the longpolling
request (/point_of_sale/get_serialized_order). It should match the
same protocol as the page was loaded in to avoid Mixed Content errors.

closes odoo/odoo#32528

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

addons/hw_screen/static/src/js/worker.js

@@ -9,7 +9,7 @@
         function longpolling() {
             $.ajax({
                 type: 'POST',
-                url: 'http://'+window.location.host+'/point_of_sale/get_serialized_order',
+                url: window.location.origin+'/point_of_sale/get_serialized_order',
                 dataType: 'json',
                 beforeSend: function(xhr){xhr.setRequestHeader('Content-Type', 'application/json');},
                 data: JSON.stringify({jsonrpc: '2.0'}),