Revert "Support toggling Taskbar All Apps with 3P Launcher."

This reverts commit 176f186a6d.

Reason for revert: DroidMonitor: Potential culprit for http://b/331438065 - verifying through ABTD before revert submission. This is part of the standard investigation process, and does not mean your CL will be reverted.

Change-Id: Ie375277ad2f65199749f0211ab50037d4b37e664
Merged-In: Ie375277ad2f65199749f0211ab50037d4b37e664

quickstep/src/com/android/launcher3/taskbar/LauncherTaskbarUIController.java

@@ -413,13 +413,6 @@ public class LauncherTaskbarUIController extends TaskbarUIController {
         return mTaskbarLauncherStateController.isInOverview();
     }
 
-    @Override
-    protected boolean canToggleHomeAllApps() {
-        return mLauncher.isResumed()
-                && !mTaskbarLauncherStateController.isInOverview()
-                && !mLauncher.areFreeformTasksVisible();
-    }
-
     @Override
     public RecentsView getRecentsView() {
         return mLauncher.getOverviewPanel();