Check wether we can scroll vertically in the drag direction (#173)

Co-authored-by: dtvc87 <dtvc87@gmail.com>

Author: dtvc87

constraintlayout/constraintlayout/src/main/java/androidx/constraintlayout/motion/widget/MotionLayout.java

@@ -2921,7 +2921,7 @@ public void onNestedPreScroll(@NonNull View target, int dx, int dy, @NonNull int
 
         if (scene.getMoveWhenScrollAtTop()) {
             // This blocks transition during scrolling
-            if ((mTransitionPosition == 1 || mTransitionPosition == 0) && target.canScrollVertically(-1)) {
+            if ((mTransitionPosition == 1 || mTransitionPosition == 0) && target.canScrollVertically(dy)) {
                 return;
             }
         }