Chrome: Don't announce 'list' on every line of ul, dl and ol tags in contenteditables (#11605)
* Ensure that ul, dl and ol tags in Chrome get the readonly state so that 'list' is not announced on every line when in a contenteditable.
* Add system test for #7562
* Fix linting issues
* Improve docstring
* Chrome system tests: The Before and After markers are now paragraphs rather than buttons. They no longer need to be focusable as we use f6 not tab.
* System test NVDA configs: disable browse mode passThroughAudioIndication, which then means that switching between browse and focus modes produces a spoken string we can check for.
* System test i7562: explicitly force focus mode at the beginning to ensure we don't accidentally test in browse mode.
* Fix linting issues
* Update what's new