fix: 加入购物车skuid可选

src/main/java/com/chaozhanggui/system/cashierservice/service/CartService.java

@@ -386,7 +386,7 @@ public class CartService {
                     return Result.fail("该商品不存在");
                 }
                 // 判断商品是否已下架
-                tbProductSkuWithBLOBs = productSkuMapper.selectByPrimaryKey(Integer.valueOf(skuId));
+                tbProductSkuWithBLOBs = StrUtil.isBlank(skuId) ? null: productSkuMapper.selectByPrimaryKey(Integer.valueOf(skuId));
                 if (tbProductSkuWithBLOBs == null || tbProductSkuWithBLOBs.getIsGrounding().equals(0)) {
                     rmCart(jsonObject, skuId, tableCartKey);
                     return Result.fail("商品已下架");