[fuchsia][scenic] Fix invalid viewRef error in pointer injection. (#36850)

This CL fixes the bug in pointer injector delegate where the viewRef is
incorrectly cloned in the flatland platform view, causing an invalid
viewRef to be passed in the Fidl request.

Test: flutter-embedder-test

Author: shivesh-ganju

shell/platform/fuchsia/flutter/flatland_platform_view.cc

@@ -154,10 +154,11 @@ void FlatlandPlatformView::OnChildViewViewRef(
     fuchsia::ui::views::ViewRef view_ref) {
   FML_CHECK(child_view_info_.count(content_id) == 1);
 
-  focus_delegate_->OnChildViewViewRef(view_id, std::move(view_ref));
-
   fuchsia::ui::views::ViewRef view_ref_clone;
   fidl::Clone(view_ref, &view_ref_clone);
+
+  focus_delegate_->OnChildViewViewRef(view_id, std::move(view_ref));
+
   pointer_injector_delegate_->OnCreateView(view_id, std::move(view_ref_clone));
   OnChildViewConnected(content_id);
 }