Fixed the clipTopAmount when transforming into the shelf

The clipTopAmount shouldn't apply to notifications in the shelf,
since otherwise the background may flicker.

Change-Id: Ifac2b821896eaaeea81e44847579d8ec0ced816d
Test: expand notification, such that the background appears when being gone before, observe no clipping.
Bug: 32437839

packages/SystemUI/src/com/android/systemui/statusbar/stack/StackScrollAlgorithm.java

@@ -140,7 +140,7 @@ public class StackScrollAlgorithm {
             float newNotificationEnd = newYTranslation + newHeight;
             boolean isHeadsUp = (child instanceof ExpandableNotificationRow)
                     && ((ExpandableNotificationRow) child).isPinned();
-            if (newYTranslation < previousNotificationEnd
+            if (!state.inShelf && newYTranslation < previousNotificationEnd
                     && (!isHeadsUp || ambientState.isShadeExpanded())) {
                 // The previous view is overlapping on top, clip!
                 float overlapAmount = previousNotificationEnd - newYTranslation;