fix(android): use dispatchDraw so that drawing is done on top of children

Author: farfromrefuge

packages/ui-canvas/platforms/android/java/com/akylas/canvas/CanvasView.java

@@ -22,8 +22,8 @@ protected void onSizeChanged(int w, int h, int oldw, int oldh) {
     }
 
     @Override
-    protected void onDraw(Canvas canvas) {
-        super.onDraw(canvas);
+    protected void dispatchDraw(Canvas canvas) {
+        super.dispatchDraw(canvas);
         if (drawListener != null) {
             drawListener.onDraw(canvas);
         }