TUN-8374: Close UDP socket if registration fails

If cloudflared was unable to register the UDP session with the
edge, the socket would be left open to be eventually closed by the
OS, or garbage collected by the runtime. Considering that either of
these closes happened significantly after some delay, it was causing
cloudflared to hold open file descriptors longer than usual if continuously
unable to register sessions.

connection/quic.go

@@ -324,6 +324,7 @@ func (q *QUICConnection) RegisterUdpSession(ctx context.Context, sessionID uuid.
 
 	session, err := q.sessionManager.RegisterSession(ctx, sessionID, originProxy)
 	if err != nil {
+		originProxy.Close()
 		log.Err(err).Str("sessionID", sessionID.String()).Msgf("Failed to register udp session")
 		tracing.EndWithErrorStatus(registerSpan, err)
 		return nil, err