Restore fallback Overview state when restarted by theme changes

- Moved RUNTIME_STATE_RECREATE_TO_UPDATE_THEME to StatefulActivity
- Handle uiMode in RecentsActivity
- When RecentsActivity is recreated due to theme changes, restore previous state

Fix: 382072029
Test: Manual: Change light/dark them from QuickSettings while in fallback Overview, Overview stay open
Flag: EXEMPT bugfix
Change-Id: Ia596150afa1436c4a25e94fd2b6930a8ded0b0d4