connecting/validateXXX

### 功能描述

官方链接：https://x6.antv.antgroup.com/tutorial/basic/interacting#validatexxx

目前 validateXXX 只支持同步程序，我想从服务端获取某个节点的依赖关系，从而判断是否可以进行连线

目前是做不到这个功能的

### 期望解决方案

希望 validateXXX 函数们 可以支持返回一个 Promise 如果 reslove 代表即可连线 如果返回的 reject 代表不可以连线

Start with the validateXXX entry points described in the linked official documentation and trace their implementation. Determine how asynchronous validation would be represented, then verify that resolved and rejected Promises produce the requested connection outcomes. No source file or test is named in the issue, so identify the relevant tests before implementation.

Written by the indexing model from the issue text.