message: Increase the `broadcast_requests` metric in the correct place
diff: @@ -376,6 +376,7 @@ where
  /// Queues a message to be sent to all nodes.
  fn broadcast_message(&self, msg: Arc<Message<P>>) {
  + self.net_metrics.broadcast_requests.inc();
  for peer_id in self.outgoing_manager.connected_peers() {
  self.send_message(peer_id, msg.clone(), None);
  }
  @@ -944,7 +945,6 @@ where
  auto_closing_responder,
  } => {
  // We're given a message to broadcast.
  - self.net_metrics.broadcast_requests.inc();
  self.broadcast_message(Arc::new(Message::Payload(*payload)));
  auto_closing_responder.respond(()).ignore()
  }
  @@ -1093,7 +1093,6 @@ where
  }
  Event::SyncFinished => {
  info!("notifying peers that chain sync has finished");
  - self.net_metrics.broadcast_requests.inc();
  self.broadcast_message(Arc::new(Message::SyncFinished));
  self.synchronization_in_progress = false;
  Effects::new()
  