[flexiglass] new defaultOverscrollProgressConverter

This new overscroll progress starts linearly with some resistance and
slowly approaches 0.2f.
Before and after attached to b/299343829#comment6

Test: Manually tested on Flexiglass
Bug: 299343829
Flag: com.android.systemui.scene_container
Change-Id: Ifc96ebc63a0b2a714323065f11709d2209f72470