message: [network] Use HashMap::entry in PeerManager::add_peer
  Instead of removing and adding the current connection to check if there
  is a simultaneous dial, we use HashMap::entry API.
  Closes:
  Approved by: davidiw
diff: @@ -529,13 +529,15 @@ where
  let mut send_new_peer_notification = true;
  // Check for and handle simultaneous dialing
  - if let Some((curr_connection, peer_handle)) = self.active_peers.remove(&peer_id) {
  + if let Entry::Occupied(active_entry) = self.active_peers.entry(peer_id) {
  + let (curr_conn_metadata, _) = active_entry.get();
  if Self::simultaneous_dial_tie_breaking(
  self.own_peer_id,
  peer_id,
  - curr_connection.origin,
  + curr_conn_metadata.origin(),
  conn_meta.origin,
  ) {
  + let (_, peer_handle) = active_entry.remove();
  // Drop the existing connection and replace it with the new connection
  drop(peer_handle);
  info!(
  @@ -565,9 +567,6 @@ where
  };
  };
  self.executor.spawn(drop_fut);
  - // Put the existing connection back
  - self.active_peers
  - .insert(peer_id, (curr_connection, peer_handle));
  return;
  }
  }
  