These controls toggle the visibility of the update progress: they perform an action
therefore they should be buttons. Also:
- uses `aria-expanded` to communicate the toggle button state
- removes some inline JavaScript
- when clicking the toggle buttons, the progress details get moved with JavaScript after the button: this helps users of assistive technologies in finding them and makes the UI a bit more intuitive
Props Cheffheid, afercia.
See #26504.
Fixes#40453.
Built from https://develop.svn.wordpress.org/trunk@40646
git-svn-id: http://core.svn.wordpress.org/trunk@40507 1a063a9b-81f0-0310-95a4-ce76da25c4cd
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