Find element in multilevel shadows

[Psvensso]

Fixes #470 #463

[iahu]

这个改动导致 antd 的 Popover 在 trigger 为 click 时，点击 popup 内的 webComponent 组件直接关闭弹窗。

[Psvensso]

@iahu Can not reproduce what you mean, can you give an example?

Stackblitz with two layers of shadow:
https://stackblitz.com/edit/react-zuo2ca?file=demo.tsx

[iahu]

@iahu Can not reproduce what you mean, can you give an example?

Stackblitz with two layers of shadow: https://stackblitz.com/edit/react-zuo2ca?file=demo.tsx

@Psvensso try to pass a custom-element to the content property. here is a online demo.

I have created a PR to fix this issue, but have't write the test case. open to review now.