chainntnfs/tx_notifier: mark rescan as complete for transactions confirmed at tip

In this commit, we mark the rescan status for a transaction as complete
if we happen to detect it has confirmed within a new block that extends
the chain. We do this as otherwise, it's possible for us to not
immediately dispatch the notification upon a subsequent registration due
to the rescan state machine.

chainntnfs/txconfnotifier.go

@@ -500,6 +500,7 @@ func (tcn *TxConfNotifier) ConnectTip(blockHash *chainhash.Hash,
 			TxIndex:     uint32(tx.Index()),
 		}
 
+		confSet.rescanStatus = rescanComplete
 		confSet.details = details
 		for _, ntfn := range confSet.ntfns {
 			ntfn.details = details