am: IsVrModeEnabled & SetVrModeEnabled fixes

Return the proper state of vr mode for IsVrModeEnabled
We should not return an error for SetVrModeEnabled. When VR Mode is turned on, it signals to lbl to turn vr mode on, not return an error code

src/core/hle/service/am/am.h

@@ -191,6 +191,7 @@ private:
 
     Core::System& system;
     std::shared_ptr<AppletMessageQueue> msg_queue;
+    bool vr_mode_state{};
 };
 
 class IStorageImpl {