Platform bindings for `within` expression

[chloekraw]

Tracking the development of platform bindings for the new within expression (mapbox/mapbox-gl-native#16157; mapbox/mapbox-gl-native#16194)

If it's possible, because this isn't too complex, it would be great to get this merged this week before the next alpha release.

cc @mapbox/maps-android @zmiao

[chloekraw]

ah whoops, totally missed that @tobrun already opened this issue on android. sorry! I didn't see the ticket on the project board.