As part of the [Material 3 specification](https://m3.material.io/components/bottom-sheets/overview) there are updates to bottom sheet's visuals: <img width="400" alt="unnamed-1" src="https://user-images.githubusercontent.com/19588/189825600-d2a8a8ba-b3d9-483c-9d45-edfcdb06e89d.png"> We should update the `BottomSheet` widget to support this Material 3 look and tokens.