Defines minimum and maximum sizes for a BottomSheet.
Typically a bottom sheet will cover the entire width of its parent. Consider limiting the width by setting smaller constraints for large screens.
If null, then the ambient ThemeData.bottomSheetTheme's BottomSheetThemeData.constraints will be used. If that is null then the bottom sheet's size will be constrained by its parent (usually a Scaffold).
If constraints are specified (either in this property or in the theme), the bottom sheet will be aligned to the bottom-center of the available space. Otherwise, no alignment is applied.
final BoxConstraints? constraints;