Set final crop on wallpaper instead of intersect clip with stack bounds

Wallpaper's clip rect is offset by its window offsets, it can't be
intersect directly with stack bounds.

bug: 28763785
Change-Id: Id87d668c9e59832498c9c62730617d0a5a9207c2

services/core/java/com/android/server/wm/WindowStateAnimator.java

@@ -1333,7 +1333,7 @@ class WindowStateAnimator {
                     final TaskStack stack = task.mStack;
                     if (stack != null && !stack.isFullscreen()) {
                         stack.getDimBounds(mTmpStackBounds);
-                        clipRect.intersect(mTmpStackBounds);
+                        finalClipRect.set(mTmpStackBounds);
                     }
                 }
             }