Android: Fix setting read during play with local game layer active

[JosJuice]

During emulation, when LocalGame has a value but CurrentRun doesn't, we want to read from LocalGame, not CurrentRun. This change exposes a LAYER_ACTIVE option that handles this correctly.

[JosJuice]

To clarify what the bug is, here are reproduction steps:

1. Turn on Show FPS in the game-specific settings for some game.
2. Start that game.
3. Open the graphics settings. Observe that Show FPS shows up as disabled, even though the FPS actually is being displayed.

[Ebola16]

I still need to get more familiar with the new config system to understand how changes can potentially go wrong but this makes sense to me.