fix(kad): reduce noise of "remote supports our protocol" log

This PR changes the logging of the Kademlia connection handler related to the remote Kademlia mode changes:
- Downgrade log level for the remote kademlia protocol report from `info` to `debug`.
- Introduce connection_id for the handler to improve logging.

Pull-Request: #4278.

swarm/src/connection.rs

@@ -53,6 +53,7 @@ use libp2p_core::upgrade::{NegotiationError, ProtocolError};
 use libp2p_core::Endpoint;
 use libp2p_identity::PeerId;
 use std::collections::HashSet;
+use std::fmt::{Display, Formatter};
 use std::future::Future;
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::task::Waker;
@@ -82,6 +83,12 @@ impl ConnectionId {
     }
 }
 
+impl Display for ConnectionId {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
 /// Information about a successfully established connection.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub(crate) struct Connected {