Is there an existing issue for this?

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Steps to reproduce

1. Enable ChromeVox and navigate through a flutter-web UI (using Search/Launch + Right arrow) to get to the "Enable accessibility" button.

Expected results

ChromeVox would ideally land directly on "Enable accessibility". This is especially important since, hearing nothing, a blind user might try using the tab key to navigate to the button, but that keypress is consumed by Flutter to handle its UI navigation instead. There's no other way to get to "Enable accessibility" except via the screen reader.

Actual results

ChromeVox silently lands on two other divs before landing on the "Enable accessibility" button. That's because the two aria-live elements for announcements appear before the "Enable accessibility" button. It's more common to place these at the end of the web page instead.