Only show split button for single fullscreen task if taskbar is present in Overview

* Taskbar in overview allows second app to be
selected so user wouldn't be stuck in split
select state

Fixes: 258543259
Test: Tested w/ flag on and off
w/ one and multiple flags
w/ fullscreen and split single focused task

Change-Id: Ie588ad66fde4e012e08d8f5abbe1eef5a1a5db6b
diff --git a/quickstep/src/com/android/quickstep/views/RecentsView.java b/quickstep/src/com/android/quickstep/views/RecentsView.java
index 6286374..ff0c984 100644
--- a/quickstep/src/com/android/quickstep/views/RecentsView.java
+++ b/quickstep/src/com/android/quickstep/views/RecentsView.java
@@ -3544,7 +3544,8 @@
         mActionsView.updateHiddenFlags(HIDDEN_SPLIT_SELECT_ACTIVE, isSplitSelectionActive());
         mActionsView.updateSplitButtonHiddenFlags(FLAG_IS_NOT_TABLET,
                 !mActivity.getDeviceProfile().isTablet);
-        mActionsView.updateSplitButtonDisabledFlags(FLAG_SINGLE_TASK, getTaskViewCount() <= 1);
+        mActionsView.updateSplitButtonDisabledFlags(FLAG_SINGLE_TASK,
+                !FeatureFlags.ENABLE_TASKBAR_IN_OVERVIEW.get() && getTaskViewCount() <= 1);
     }
 
     /**