Enable live tile in 3 button mode

- Previously we rely on whether launcher is resumed as a signal to see what "toggle" means. This no longer works since launcher is not resumed in Overview. Instead, we need to check the live tile signals.
- Use screenshot doesn't propagate after setting a new current task. So followed the logic around mRunningTaskIconScaledDown to work it out.
- Get rid of NavigationModeFeatureFlag, pending on 3rd party launcher change ag/14409355

Fixes: 185934639
Test: (1) Toggle overview from home screen and toggle back to fullscreen. (2) Toggle overview from app and keep toggling.

Change-Id: Iffaea18afb2179b5bb7dadda49e56efefa5658bc
Merged-In: Iffaea18afb2179b5bb7dadda49e56efefa5658bc