Fix GetOrdersByShipperId bug

Author: pmoleri

NorthwindCRUD/Controllers/OrdersController.cs

@@ -222,9 +222,9 @@ public ActionResult<CustomerDto> GetShipperByOrderId(int id)
             try
             {
                 var order = this.orderService.GetById(id);
-                if (order != null)
+                if (order?.ShipperId != null)
                 {
-                    var shipper = this.shipperService.GetById(order.ShipVia);
+                    var shipper = this.shipperService.GetById(order.ShipperId.Value);
 
                     if (shipper != null)
                     {

NorthwindCRUD/Services/OrderService.cs

@@ -73,7 +73,7 @@ public OrderDb[] GetOrdersByEmployeeId(int id)
         public OrderDb[] GetOrdersByShipperId(int id)
         {
             return GetOrdersQuery()
-                .Where(o => o.ShipVia == id)
+                .Where(o => o.ShipperId == id)
                 .ToArray();
         }