Fix _endRecording native return type (#34891)

diff --git a/lib/ui/painting.dart b/lib/ui/painting.dart
index 6589c90..3336554 100644
--- a/lib/ui/painting.dart
+++ b/lib/ui/painting.dart
@@ -5661,7 +5661,7 @@
     return picture;
   }
 
-  @FfiNative<Handle Function(Pointer<Void>, Handle)>('PictureRecorder::endRecording')
+  @FfiNative<Void Function(Pointer<Void>, Handle)>('PictureRecorder::endRecording')
   external void _endRecording(Picture outPicture);
 
   Canvas? _canvas;