Issue

When multiple modals stack in tabster@>=8.3.0, each modal is assigned aria-hidden="true". As a result, tools like screen.getByRole cannot locate the dialogs, potentially causing real-world accessibility concerns (unverified).

Steps to Reproduce

1. Run npm install; [email protected] installs via @fluentui/react-tabster.
2. Run npm run test to observe the issue.

Removing node_modules/@fluentui/react-tabster/node_modules discards the local [email protected], reverting all references to [email protected]. Run npm run test again to see the test pass.