04f26f4377
I am unsure why the `tabindex` was removed when semantics were enabled. It seems this change was made without a clear explanation (by me). This PR shouldn't cause any issues as Flutter Views already have a tabindex, we're not adding a new one. This change is necessary because the semantics text strategy refocuses the view on deactivation, requiring the Flutter view to be focusable. ThIs PR is a requirement to enable https://github.com/flutter/engine/pull/54966. https://github.com/flutter/flutter/issues/153022 [C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style