message: Fix seg fault in custom user data refresh
diff: @@ -427,7 +427,7 @@ void SyncUser::set_binding_context_factory(SyncUserContextFactory factory)
  void SyncUser::refresh_custom_data(std::function<void(util::Optional<app::AppError>)> completion_block)
  {
  if (auto app = m_sync_manager->app().lock()) {
  - app->refresh_custom_data(shared_from_this(), [&](auto error) {
  + app->refresh_custom_data(shared_from_this(), [completion_block, this](auto error) {
  emit_change_to_subscribers(*this);
  completion_block(error);
  });
  