[web] on Safari for macOS using VoiceOver it is easy to make text field non-editable #147439

On Safari for macOS using VoiceOver it is easy to get a text field into a non-editable state. The text field is seemingly focused and being edited according to the spoken text by VoiceOver, but nothing happens visually.

Repro code: the TextField demo in the a11y_assessments app.
Live app: https://fwa11y.web.app/

It may take a few attempts, but to reproduce try to focus on the text field using VoiceOver shortcuts (Control + Option + arrow keys) and begin editing. If it doesn't happen right away, move focus out, then move it back into the field and try editing again. Eventually it enters the bad state.