fix：【mall】分销用户创建时，缺少对 bindUserId 的校验

yudao-module-mall/yudao-module-trade/src/main/java/cn/iocoder/yudao/module/trade/controller/admin/brokerage/vo/user/BrokerageUserCreateReqVO.java

@@ -13,6 +13,7 @@ public class BrokerageUserCreateReqVO {
     private Long userId;
 
     @Schema(description = "推广员编号", requiredMode = Schema.RequiredMode.REQUIRED, example = "4587")
+    @NotNull(message = "推广员编号不能为空")
     private Long bindUserId;
 
 }