Fix emulator not emitting folding features. Emitting the fold state was
removed since it works differently for emulators. Emulators write to
settings while the reference implementation reads the value from
DeviceStateManager. Update the setting producer to also read the state
from settings.
Bug: 218872245
Test: Manual - open window manager samples on an emulator.
Change-Id: I7def87bd406c2ae5b1ac27be58a3b22a239c3e82
5e0a25ea58