itest: add coverage for blinded error resolution from on-chain failure

This itest adds a test that we still propagate blinded errors back
properly after a restart with an on-chain resolution. The test also
updates our sendpayment timeout to longer so that there's time to
resolve the on chain claim.

itest/list_on_test.go

@@ -582,6 +582,10 @@ var allTestCases = []*lntest.TestCase{
 		Name:     "disable introduction node",
 		TestFunc: testDisableIntroductionNode,
 	},
+	{
+		Name:     "on chain to blinded",
+		TestFunc: testErrorHandlingOnChainFailure,
+	},
 	{
 		Name:     "removetx",
 		TestFunc: testRemoveTx,