ensure game is fully unloaded before calling rc_client_logout

[Jamiras]

Fixes a crash that occurs if the Logout menu option is used while a game is loaded with active assets.

When logging out, the underlying game data is destroyed, but the Models were not being destroyed. When the emulator calls DoFrame, we attempt to update the Models to keep them in sync with the underlying data. Solution: unload game from Asset List when logging out to destroy models.