Rememeber the last dark mode before shutdown when in auto mode

Twilight mode is not available when the phone starts. So the last state
is rememebered until the phone screen turns off

Fixes: 160842085
Test: manual testing
Merged-In: I78a490c0f083e92022e1995b3e19dc7dd567a7c3
Change-Id: I78a490c0f083e92022e1995b3e19dc7dd567a7c3
(cherry picked from commit 7bddda48)