Set draw drop shadow for vector pointer icons when sprite is set.

Drop shadow was not being retained when reloading pointers, like when
the display size changes.

Bug: 305193969
Test: Manual
Flag: ACONFIG com.android.systemui.enable_vector_cursors STAGING
Change-Id: Ic6c80166df0d64ca5709aac7ca401f442564698d
diff --git a/libs/input/SpriteController.h b/libs/input/SpriteController.h
index 04ecb38..35776e9 100644
--- a/libs/input/SpriteController.h
+++ b/libs/input/SpriteController.h
@@ -151,6 +151,7 @@
         DIRTY_HOTSPOT = 1 << 6,
         DIRTY_DISPLAY_ID = 1 << 7,
         DIRTY_ICON_STYLE = 1 << 8,
+        DIRTY_DRAW_DROP_SHADOW = 1 << 9,
     };
 
     /* Describes the state of a sprite.