htlcswitch: add final htlc event to notifier

contractcourt/mock_htlcnotifier_test.go

@@ -0,0 +1,11 @@
+package contractcourt
+
+import "github.com/lightningnetwork/lnd/channeldb"
+
+type mockHTLCNotifier struct {
+	HtlcNotifier
+}
+
+func (m *mockHTLCNotifier) NotifyFinalHtlcEvent(key channeldb.CircuitKey,
+	info channeldb.FinalHtlcInfo) { // nolint:whitespace
+}