Allow to remove items from the basket setting quantity to zero

src/ApplicationCore/Entities/BasketAggregate/Basket.cs

@@ -25,5 +25,10 @@ namespace Microsoft.eShopWeb.ApplicationCore.Entities.BasketAggregate
             var existingItem = Items.FirstOrDefault(i => i.CatalogItemId == catalogItemId);
             existingItem.Quantity += quantity;
         }
+
+        public void RemoveEmptyItems()
+        {
+            _items.RemoveAll(i => i.Quantity == 0);
+        }
     }
 }

src/ApplicationCore/Services/BasketService.cs

@@ -59,10 +59,11 @@ namespace Microsoft.eShopWeb.ApplicationCore.Services
             {
                 if (quantities.TryGetValue(item.Id.ToString(), out var quantity))
                 {
-                    _logger.LogInformation($"Updating quantity of item ID:{item.Id} to {quantity}.");
+                    if(_logger != null) _logger.LogInformation($"Updating quantity of item ID:{item.Id} to {quantity}.");
                     item.Quantity = quantity;
                 }
             }
+            basket.RemoveEmptyItems();
             await _basketRepository.UpdateAsync(basket);
         }