[FIX] pos_restaurant: avoid double order in backend.

This fix removed the duplicates of an empty order when using the floor management. Before, when syncing order without order lines, it was creating an empty order in the backend.
When reloading the table, it was creating a new empty order, ignoring the previous one. That problem lead to empty unpaid draft order.

closes odoo/odoo#57952

Task-id: 2308862
Signed-off-by: Masereel Pierre <pim@odoo.com>

addons/point_of_sale/static/src/js/db.js

@@ -516,7 +516,7 @@ var PosDB = core.Class.extend({
         var saved = this.load('unpaid_orders',[]);
         var orders = [];
         saved.forEach(function(o) {
-            if (ids.includes(o.id) && (o.data.server_id || o.data.lines.length)){
+            if (ids.includes(o.id)){
                 orders.push(o);
             }
         });

addons/pos_restaurant/static/src/js/floors.js

@@ -236,11 +236,9 @@ models.PosModel = models.PosModel.extend({
                 }
             });
             server_orders.forEach(function(server_order){
-                if (server_order.lines.length){
-                    var new_order = new models.Order({},{pos: self, json: server_order});
-                    self.get("orders").add(new_order);
-                    new_order.save_to_db();
-                }
+                var new_order = new models.Order({},{pos: self, json: server_order});
+                self.get("orders").add(new_order);
+                new_order.save_to_db();
             })
             if (!ids_to_remove.length) {
                 self.set_synch('connected');