Drop disconnecting peers from the list of ignored peers

When a peer misbehaves/sends bogus data we reply with an error message
and insert it to the ignored list.

Here, we avoid having this list grow unboundedly over time by removing
peers again once they disconnect, allowing them a second chance upon
reconnection.

Author: tnull

lightning-liquidity/src/manager.rs

@@ -618,6 +618,9 @@ where
 	}
 
 	fn peer_disconnected(&self, counterparty_node_id: bitcoin::secp256k1::PublicKey) {
+		// If the peer was misbehaving, drop it from the ignored list to cleanup the kept state.
+		self.ignored_peers.write().unwrap().remove(&counterparty_node_id);
+
 		if let Some(lsps2_service_handler) = self.lsps2_service_handler.as_ref() {
 			lsps2_service_handler.peer_disconnected(counterparty_node_id);
 		}