Fix memory leak in TaskbarLauncherStateController

mIconAlphaForHome.setConsumer(null) in onDestroy()

Test: Run BinderTests#testSwitchToOverview locally
Bug: 206633573
Change-Id: I912cd66097b113ee84197f23a5862e333d7e63f2
diff --git a/quickstep/src/com/android/launcher3/taskbar/TaskbarLauncherStateController.java b/quickstep/src/com/android/launcher3/taskbar/TaskbarLauncherStateController.java
index 2693bc3..152b255 100644
--- a/quickstep/src/com/android/launcher3/taskbar/TaskbarLauncherStateController.java
+++ b/quickstep/src/com/android/launcher3/taskbar/TaskbarLauncherStateController.java
@@ -115,6 +115,7 @@
         mIconAlignmentForGestureState.finishAnimation();
         mIconAlignmentForLauncherState.finishAnimation();
 
+        mIconAlphaForHome.setConsumer(null);
         mLauncher.getHotseat().setIconsAlpha(1f);
         mLauncher.getStateManager().removeStateListener(mStateListener);
     }