Don't re-launch stopped activities while the device is sleeping

Don't ensure configuration for stopped activities while the device
is sleeping as we don't want to relaunch activities in this state.
Note that the right configuration will be applied to the activity
the next time we try to make it visible. The re-launch will happen
then.

Bug: 28518380

Change-Id: Id79d7817ba8f213d89cae6964de09cafe17481f9