itest: add coverage for failure at the introduction node

itest/list_on_test.go

@@ -574,6 +574,10 @@ var allTestCases = []*lntest.TestCase{
 		Name:     "relayer blinded error",
 		TestFunc: testRelayingBlindedError,
 	},
+	{
+		Name:     "introduction blinded error",
+		TestFunc: testIntroductionNodeError,
+	},
 	{
 		Name:     "removetx",
 		TestFunc: testRemoveTx,