Update p2p_listen_address in args.rs

A line in args.rs was altered to set the p2p_listen_address in the config. Previously, this field was not being set. Now, it is set to the given 'listen' argument value, falling back to an Unspecified ContextualNetAddress if 'listen' is not given. This change ensures that the p2p_listen_address is always defined.

kaspad/src/args.rs

@@ -127,6 +127,7 @@ impl Args {
         config.user_agent_comments = self.user_agent_comments.clone();
         config.block_template_cache_lifetime = self.block_template_cache_lifetime;
 
+        config.p2p_listen_address = self.listen.unwrap_or(ContextualNetAddress::unspecified());
         #[cfg(feature = "devnet-prealloc")]
         if let Some(num_prealloc_utxos) = self.num_prealloc_utxos {
             config.initial_utxo_set = Arc::new(self.generate_prealloc_utxos(num_prealloc_utxos));