itest+lntest: add grpc NotFound error code test

itest/list_on_test.go

@@ -715,6 +715,10 @@ var allTestCases = []*lntest.TestCase{
 		Name:     "peer bootstrapping",
 		TestFunc: testPeerBootstrapping,
 	},
+	{
+		Name:     "grpc not found",
+		TestFunc: testGRPCNotFound,
+	},
 }
 
 // appendPrefixed is used to add a prefix to each test name in the subtests