Only support manual stashing while in app

- For taskbar in overview, don't allow stashing

Fix: 253042515
Test: With taskbar in overview, long press do nothing. Taskbar is still stashable in app
Test: Without taskbar in overview, taskbar still transform to nav handle in overview
Change-Id: I8f353a473a8570df72acda2338c4b984a69dc5c0
diff --git a/quickstep/src/com/android/launcher3/taskbar/TaskbarStashController.java b/quickstep/src/com/android/launcher3/taskbar/TaskbarStashController.java
index 98a1b01..9fd2bf9 100644
--- a/quickstep/src/com/android/launcher3/taskbar/TaskbarStashController.java
+++ b/quickstep/src/com/android/launcher3/taskbar/TaskbarStashController.java
@@ -242,6 +242,7 @@
      */
     protected boolean supportsManualStashing() {
         return supportsVisualStashing()
+                && isInApp()
                 && (!Utilities.IS_RUNNING_IN_TEST_HARNESS || mEnableManualStashingDuringTests);
     }