Add collapseOnFlingDown parameter to FlexibleSheetState

[terrakok]

Introduce the collapseOnFlingDown property to control whether the bottom sheet collapses on a downward fling gesture. Updated constructors, property initializations, and logic to use this parameter, ensuring greater flexibility for sheet behavior customization.

val sheetState = rememberFlexibleBottomSheetState(
  collapseOnFlingDown = false //by default = !isModal
)

Before, the behavior depended on type of the bottom sheet:

• for isModal=true downward fling gestures didn't collapse the bottomsheet unless inner scroll is ended
• for isModal=false the gestures always collapsed the bottomsheet to the possible smaller state

You will see the difference below:

collapseOnFlingDown = true	collapseOnFlingDown = false
Screen.Recording.2025-01-12.at.23.30.02.mp4	Screen.Recording.2025-01-12.at.23.30.27.mp4