chore(ln-dlc-node): Add unit to tracing field name

crates/ln-dlc-node/src/ldk_node_wallet.rs

@@ -130,7 +130,7 @@ where
         let height = self.blockchain.get_height()?;
 
         tracing::info!(
-            duration = now.elapsed().as_millis(),
+            duration_ms = now.elapsed().as_millis(),
             latest_height = height,
             "Finished on-chain sync",
         );