This PR is extracted from #23346 to address some unclear (I don't
understand) code-belonging concerns.
This PR needs to be backported, otherwise the `aria.js` is too buggy in
some cases. Since there would be two minor conflicts, I will do the
backport manually.
Before: the `aria.js` is still buggy in some cases.
After: tested with AppleVoice, Android TalkBack
* Fix incorrect dropdown init code
* Fix incorrect role element (the menu role should be on the `$menu`
element, but not on the `$focusable`)
* Fix the focus-show-click-hide problem on mobile. Now the language menu
works as expected
* Fix incorrect dropdown template function setting
* Clarify the logic in aria.js
* Hide item's tippy after menu gets hidden
* Fix incorrect tippy `setProps` after `destroy`
* Fix UI lag problem when page gets redirected during menu hiding
animation with screen reader
* Improve comments
* Implement the layout proposed by #19861
<details>
d74a7efb60/web_src/js/features/aria.md (L38-L47)
</details>
345aa09756