Invalid check of IOUState on full settlement flow

[ooharawork]

corda-training-template/kotlin-source/src/main/kotlin/net/corda/training/flow/IOUSettleFlow.kt

Lines 49 to 52 in 9adee32

	val signedTransactionFlow = object : SignTransactionFlow(flowSession) {
	override fun checkTransaction(stx: SignedTransaction) = requireThat {
	val outputStates = stx.tx.outputs.map { it.data::class.java.name }.toList()
	"There must be an IOU transaction." using (outputStates.contains(IOUState::class.java.name))

In the case of full settlement, the transaction must not contain an IOUState in output, therefore the code above produces an error.

The check should be removed as in corda-training-solutions, or modified such that the check is made only when in a partial settlement.

BTW I don't have much expertise on Corda so not sure but, I doubt that that check is really required here, because we have already similar checks in IOUContract.