pointer: Update the button count after repicking

The default focus interface uses the button count to determine
whether we should update the pointer focused surface. When releasing
an implicit grab, we need to send the button release events to the
implicitly grabbed surface, so we can't reset the focus surface too
soon. We already explicitly set the focus at the end of implicit
grabs, so counting the buttons after is perfectly fine.

src/wayland/meta-wayland-pointer.c

@@ -300,10 +300,10 @@ void
 meta_wayland_pointer_update (MetaWaylandPointer *pointer,
                              const ClutterEvent *event)
 {
-  pointer->button_count = count_buttons (event);
-
   repick_for_event (pointer, event);
 
+  pointer->button_count = count_buttons (event);
+
   if (pointer->cursor_tracker)
     {
       ClutterPoint pos;