Revert "Fix activity leak"

This reverts commit 67c807a1fead456203692fdd92526cf30ad5e1ef.

Reason for revert: <Setting the SplitSelectStateController to null causes NPE in launcher>

Fix: 342553715
Bug: 332339792
Change-Id: I10433e468948c4ba826e79baa06925fdf7dfbe5d
diff --git a/quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java b/quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java
index 5ffa4b5..4184ab2 100644
--- a/quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java
+++ b/quickstep/src/com/android/launcher3/uioverrides/QuickstepLauncher.java
@@ -533,18 +533,16 @@
         if (mDesktopVisibilityController != null) {
             mDesktopVisibilityController.unregisterSystemUiListener();
         }
-        mDesktopVisibilityController = null;
 
         if (mSplitSelectStateController != null) {
-            removeBackAnimationCallback(mSplitSelectStateController.getSplitBackHandler());
             mSplitSelectStateController.onDestroy();
         }
-        mSplitSelectStateController = null;
 
         super.onDestroy();
         mHotseatPredictionController.destroy();
         mSplitWithKeyboardShortcutController.onDestroy();
         if (mViewCapture != null) mViewCapture.close();
+        removeBackAnimationCallback(mSplitSelectStateController.getSplitBackHandler());
     }
 
     @Override