fix: closed bottom sheet snap point (by @eastroot1590)

[gorhom]

Cloned from #1035

Closed bottom sheet can't directly snap to 100% because initial animatedNextPosition is 0 and 100%'s nextPosition is 0 too.

Motivation

this kind of sheets can't open

const snapPoint = ['100%'];
const ref = useRef<BottomSheet>(null);

const handlePress = () => {
    // doesn't work
    ref.current?.snapToIndex(0);
};

return (
  <Container>
    <Button onPress={handlePress} />
    <BottomSheet
      ref={ref}
      index={-1}
      snapPoints={snapPoint}
    />
  </Container>
)

in animateToPositionCompleted, animatedNextPosition always set to Number.NEGATIVE_INFINITY so this value can be initial value.