Summary:
The `position` animated value is used for scale, translateX, and tranlateY
animations, which are all supported by NativeAnimatedHelper. Unfortunately,
native animations are incompatible with JS driven animations, which the
`enableGestures` flag enables.
This diff therefore conditionally enables native animations based on the native
module's precense, and the state of `enableGestures`.
Ideally the animations would be refactored so that they could fully leverage
native animations, as they are far superior for navigational components.
Reviewed By: oyvindkinsey
Differential Revision: D4020977
fbshipit-source-id: 8e1d015c4d41fee103469f6f9ffa02ff4f1f5517
f9779e3eb7