Show overview as grid in fallback recents

- Replace mShowAsGrid with state specific mOverviewGridEnabled and mCurrentGestureEndTarget
- Avoid showing invisible home task in grid
- Fix quick switch out of orientation in fallback recents
- Add a HOME state to switch to when starting home, to avoid showing grid overview briefly in quick switch
- Separate clear all button and overview actions handling
- Always maintain first task's fullscreen translation at 0 to avoid jumping when mOverviewFullscreenEnabled changes
- Moved fullscreenTranslation calculation to RecentsView
- Added GestureEndTarget -> BaseState translation to allow querying displayOverviewAsGrid for a displayOverviewTasksAsGrid

Bug: 174464863
Test: Launch overveiw from home, launch overveiw from app, launch into app, test for both small and large screens
Change-Id: Iee06d94d3067ea45cadd2051717223ddc0e6e70c

quickstep/src/com/android/quickstep/views/LauncherRecentsView.java

@@ -150,6 +150,8 @@ public class LauncherRecentsView extends RecentsView<BaseQuickstepLauncher>
     @Override
     public void onStateTransitionStart(LauncherState toState) {
         setOverviewStateEnabled(toState.overviewUi);
+        setOverviewGridEnabled(toState.displayOverviewTasksAsGrid(mActivity.getDeviceProfile()));
+        setOverviewFullscreenEnabled(toState.getOverviewFullscreenProgress() == 1);
         setFreezeViewVisibility(true);
     }
 
@@ -160,8 +162,6 @@ public class LauncherRecentsView extends RecentsView<BaseQuickstepLauncher>
             reset();
         }
         setOverlayEnabled(finalState == OVERVIEW || finalState == OVERVIEW_MODAL_TASK);
-        setOverviewGridEnabled(finalState.displayOverviewTasksAsGrid(mActivity));
-        setOverviewFullscreenEnabled(finalState.getOverviewFullscreenProgress() == 1);
         setFreezeViewVisibility(false);
     }