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

quickstep/src/com/android/quickstep/QuickstepProcessInitializer.java

@@ -15,8 +15,6 @@
  */
 package com.android.quickstep;
 
-import static com.android.quickstep.util.NavigationModeFeatureFlag.LIVE_TILE;
-
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.pm.PackageManager;
@@ -61,8 +59,6 @@ public class QuickstepProcessInitializer extends MainProcessInitializer {
 
         super.init(context);
 
-        LIVE_TILE.initialize(context);
-
         // Elevate GPU priority for Quickstep and Remote animations.
         ThreadedRendererCompat.setContextPriority(
                 ThreadedRendererCompat.EGL_CONTEXT_PRIORITY_HIGH_IMG);