multi: pass UpdateAddHtlc message custom records to invoice modifier

invoices/invoiceregistry.go

@@ -918,6 +918,7 @@ func (i *InvoiceRegistry) processAMP(ctx invoiceUpdateCtx) error {
 func (i *InvoiceRegistry) NotifyExitHopHtlc(rHash lntypes.Hash,
 	amtPaid lnwire.MilliSatoshi, expiry uint32, currentHeight int32,
 	circuitKey CircuitKey, hodlChan chan<- interface{},
+	wireCustomRecords lnwire.CustomRecords,
 	payload Payload) (HtlcResolution, error) {
 
 	// Create the update context containing the relevant details of the
@@ -929,6 +930,7 @@ func (i *InvoiceRegistry) NotifyExitHopHtlc(rHash lntypes.Hash,
 		expiry:               expiry,
 		currentHeight:        currentHeight,
 		finalCltvRejectDelta: i.cfg.FinalCltvRejectDelta,
+		wireCustomRecords:    wireCustomRecords,
 		customRecords:        payload.CustomRecords(),
 		mpp:                  payload.MultiPath(),
 		amp:                  payload.AMPRecord(),
@@ -1051,6 +1053,7 @@ func (i *InvoiceRegistry) notifyExitHopHtlcLocked(
 	// the interceptor's client an opportunity to manipulate the
 	// settlement process.
 	err = i.cfg.HtlcInterceptor.Intercept(HtlcModifyRequest{
+		WireCustomRecords:  ctx.wireCustomRecords,
 		ExitHtlcCircuitKey: ctx.circuitKey,
 		ExitHtlcAmt:        ctx.amtPaid,
 		ExitHtlcExpiry:     ctx.expiry,