Before: the `aria.js` is still buggy in some cases.
After: tested with AppleVoice, Android TalkBack (I tested it with 1.19
again)
* 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
* Fix incorrect tippy `setProps` after `destroy`
* Improve comments
* Implement the layout proposed by #19861