[native] introduce custom bottom sheet handle component

Summary:
Based on our designs we need to implement a custom bottom sheet handle component that can be passed to BottomSheetModal as a prop.

Designs:

Link to the docs: https://gorhom.github.io/react-native-bottom-sheet/props#handlecomponent

Depends on D8955

Test Plan:
Please see the before and after screenshots:

Before:

After:

Reviewers: atul, inka

Reviewed By: atul

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8958