multi: update to fn v2

lnrpc/devrpc/dev_server.go

@@ -16,7 +16,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/lnrpc"