Avoid unnecessary PublicKey parsing in RGS application

`PublicKey` parsing is relatively expensive as we have to check if
the point is actually on the curve. To avoid it, our `NetworkGraph`
uses `NodeId`s which don't have the validity requirement.

Here, we take advantage of that in RGS application to avoid parsing
`PublicKey`s, improving performance.

Author: TheBlueMatt

lightning-rapid-gossip-sync/src/processing.rs

@@ -3,7 +3,6 @@ use core::ops::Deref;
 use core::sync::atomic::Ordering;
 
 use bitcoin::constants::ChainHash;
-use bitcoin::secp256k1::PublicKey;
 
 use lightning::io;
 use lightning::ln::msgs::{
@@ -117,7 +116,7 @@ where
 		};
 
 		let node_id_count: u32 = Readable::read(read_cursor)?;
-		let mut node_ids: Vec<PublicKey> = Vec::with_capacity(core::cmp::min(
+		let mut node_ids: Vec<NodeId> = Vec::with_capacity(core::cmp::min(
 			node_id_count,
 			MAX_INITIAL_NODE_ID_VECTOR_CAPACITY,
 		) as usize);
@@ -154,9 +153,8 @@ where
 				let key_parity = node_detail_flag & 0b_0000_0011;
 				pubkey_bytes[0] = key_parity;
 
-				let current_pubkey = PublicKey::from_slice(&pubkey_bytes)?;
-				let current_node_id = NodeId::from_pubkey(&current_pubkey);
-				node_ids.push(current_pubkey);
+				let current_node_id = NodeId::from_slice(&pubkey_bytes)?;
+				node_ids.push(current_node_id);
 
 				if is_reminder || has_address_details || feature_detail_marker > 0 {
 					let mut synthetic_node_announcement = UnsignedNodeAnnouncement {

lightning/src/routing/gossip.rs

@@ -1992,8 +1992,8 @@ where
 	///
 	/// All other parameters as used in [`msgs::UnsignedChannelAnnouncement`] fields.
 	pub fn add_channel_from_partial_announcement(
-		&self, short_channel_id: u64, timestamp: u64, features: ChannelFeatures,
-		node_id_1: PublicKey, node_id_2: PublicKey,
+		&self, short_channel_id: u64, timestamp: u64, features: ChannelFeatures, node_id_1: NodeId,
+		node_id_2: NodeId,
 	) -> Result<(), LightningError> {
 		if node_id_1 == node_id_2 {
 			return Err(LightningError {
@@ -2002,13 +2002,11 @@ where
 			});
 		};
 
-		let node_1 = NodeId::from_pubkey(&node_id_1);
-		let node_2 = NodeId::from_pubkey(&node_id_2);
 		let channel_info = ChannelInfo {
 			features,
-			node_one: node_1.clone(),
+			node_one: node_id_1,
 			one_to_two: None,
-			node_two: node_2.clone(),
+			node_two: node_id_2,
 			two_to_one: None,
 			capacity_sats: None,
 			announcement_message: None,