Remove syncing wallet log

BDK already has a log line for the sync that we could enable if we
wanted such a log.
Additionally, _we_ are not actually syncing the wallet, bdk is so our
log line was lying. It should have said "calling bdk to sync wallet".

swap/src/bitcoin/wallet.rs

@@ -111,7 +111,6 @@ impl Wallet {
     }
 
     pub async fn sync_wallet(&self) -> Result<()> {
-        tracing::debug!("syncing wallet");
         self.inner.lock().await.sync(noop_progress(), None)?;
         Ok(())
     }