feat(webrtc): fix compilation errors

iroh/src/magicsock.rs

@@ -3553,16 +3553,18 @@ impl Actor {
             // forever like we do with the other branches that yield `Option`s
             Some(discovery_item) = discovery_events.next() => {
                 trace!("tick: discovery event, address discovered: {discovery_item:?}");
-                let provenance = discovery_item.provenance();
-                let node_addr = discovery_item.to_node_addr();
-                if let Err(e) = self.msock.add_node_addr(
-                    node_addr,
-                    Source::Discovery {
-                        name: provenance.to_string()
-                    }) {
-                    let node_addr = discovery_item.to_node_addr();
-                    warn!(?node_addr, "unable to add discovered node address to the node map: {e:?}");
-                }
+                if let DiscoveryEvent::Discovered(discovery_item) = &discovery_item {
+                        let provenance = discovery_item.provenance();
+                        let node_addr = discovery_item.to_node_addr();
+                        if let Err(e) = self.msock.add_node_addr(
+                            node_addr,
+                            Source::Discovery {
+                                name: provenance.to_string()
+                            }) {
+                            let node_addr = discovery_item.to_node_addr();
+                            warn!(?node_addr, "unable to add discovered node address to the node map: {e:?}");
+                        }
+                    }
                 // Send the discovery item to the subscribers of the discovery broadcast stream.
                 self.msock.discovery_subscribers.send(discovery_item);
             }