Updates PruneNonReactiveDependencies to treat setState functions as
non-reactive, since we know they have a stable identity. This is based on type
inference and our recently added definitions for useState and its return type,
so it's conservative and will only work when our inference can prove that the
scope dependency has the SetState type.
Note that this approach is simple and has limitations, notably the fact that the
setState is non-reactive doesn't propagate. But it's simple, trivially correct,
and already improves codegen somewhat, so i figured it's worth landing for now.
## Test Plan
Tested on internal app