[FIX] point_of_sale: fix runtime error

Steps to follow

  - Enable pos pricelists
  - Enable 'Login with Employees' and 'Advanced Pricelists'
  - Open a session
  - Select a Cashier
  - Order a product
  - Select a pricelist
  - Confirm the order
  - Lock the session
  - Select a Cashier again

  -> A stacktrace appears

Cause of the issue

  The `list` and `is_selected` options are reused from the previous
  instance
  -> The current order can be null

Solution

  Set the options before calling the super method in `show()`

opw-2649351

closes odoo/odoo#81610

Signed-off-by: Masereel Pierre <pim@odoo.com>

addons/point_of_sale/static/src/js/popups.js

@@ -174,10 +174,10 @@ var SelectionPopupWidget = PopupWidget.extend({
     show: function(options){
         var self = this;
         options = options || {};
-        this._super(options);
-
         this.list = options.list || [];
         this.is_selected = options.is_selected || function (item) { return false; };
+
+        this._super(options);
         this.renderElement();
     },
     click_item : function(event) {