fix(select): do not close the dropdown after selecting when popup bind to itself

[kaikaibenkai]

Types of changes

• New feature
• Bug fix
• Enhancement
• Component style change
• Typescript definition change
• Documentation change
• Coding style change
• Refactoring
• Test cases
• Continuous integration
• Breaking change
• Others

Background and context

fix #2564

Solution

如果挂到 <a-select> 自己，会导致用户选择后触发 MouseEvent，而正常情况下不会。

观察到 MouseEvent 的 target 是点击的选项，所以在处理 MouseEvent 时判断 target 是否 popup 的子节点。
如果是子节点，说明点击事件发生在 popup 中，也就是点击了选项，那就应该 changeVisible(false)。
如果不是子节点，说明一切正常。

How is the change tested?

see #2564

Changelog

Component	Changelog(CN)	Changelog(EN)	Related issues
select	修复 popup-container 绑定到自己时选择后不隐藏的 bug	fix the bug of not close the dropdown after selecting when popup bind to itself	Close #2564

Checklist:

• Test suite passes (npm run test)
• Provide changelog for relevant changes (e.g. bug fixes and new features) if applicable.
• Changes are submitted to the appropriate branch (e.g. features should be submitted to feature branch and others
  should be submitted to main branch)

[kaikaibenkai]

功能测试通过

但是由于 HTMLElement#contains 方法耗时较长， trigger 性能下降了

是否需要考虑一下给 trigger 加个 enable-child-verify props，手动开启这个 patch？