b/429094918

Run the https://github.com/flutter/flutter/tree/master/dev/a11y_assessments and navigate to autocomplete demo

EXPECTED RESULTS:

VoiceOver announces "Search results available, Swipe right to read the results" or similar.
OR

VoiceOver announces "Search results not available, re-enter the details correctly" or similar when there is no autocomplete results displayed.

Dynamic visual changes MUST be spoken to VoiceOver using UIAccessibility.Notification.announcem