Fix reliance on non-empty NodeInfo::endpoints (#8684)

* Use as_deref instead of .map in Node::client_version

* Fix reliance on non-empty NodeInfo::endpoints

substrate/client/network/src/peer_info.rs

@@ -138,13 +138,15 @@ pub struct Node<'a>(&'a NodeInfo);
 
 impl<'a> Node<'a> {
 	/// Returns the endpoint of an established connection to the peer.
-	pub fn endpoint(&self) -> &'a ConnectedPoint {
-		&self.0.endpoints[0] // `endpoints` are non-empty by definition
+	///
+	/// Returns `None` if we are disconnected from the node.
+	pub fn endpoint(&self) -> Option<&'a ConnectedPoint> {
+		self.0.endpoints.get(0)
 	}
 
 	/// Returns the latest version information we know of.
 	pub fn client_version(&self) -> Option<&'a str> {
-		self.0.client_version.as_ref().map(|s| &s[..])
+		self.0.client_version.as_deref()
 	}
 
 	/// Returns the latest ping time we know of for this node. `None` if we never successfully