wheel picker separators code refactor

[adids1221]

Description

WheelPicker separators was rendered above the AnimatedFlatList, which cause that the separator render over the current item.

example code snippet (from the example screen):

           <WheelPicker
            initialValue={'February'}
            activeTextColor={Colors.$textPrimary}
            inactiveTextColor={Colors.$textNeutralHeavy}
            items={monthItems}
            textStyle={Typography.text60R}
            numberOfVisibleRows={3}
            separatorsStyle={{backgroundColor: Colors.red70}}
          />

Changelog

WheelPicker separators render below the list items.

Additional info

#3028