message: temporarily downgrade log level of error message in network component
diff: @@ -709,7 +709,7 @@ pub(super) async fn message_sender<P>(
  // We should never attempt to send an unsafe message to a peer that we know is a
  // joiner. Since "unsafe" does usually not mean immediately catastrophic, we attempt
  // to carry on, but warn loudly.
  - error!(kind=%message.classify(), %addr, %node_id, "sending unsafe message to joiner");
  + warn!(kind=%message.classify(), %addr, %node_id, "sending unsafe message to joiner");
  }
  }
  