channeldb/payments_test: handle that dupe payments will always have StatusSuccess

Legacy duplicate payments would only be migrated over if they had
succeeded. Alter the test to reflect this.

channeldb/payment_control_test.go

@@ -466,7 +466,7 @@ func TestPaymentControlDeleteNonInFligt(t *testing.T) {
 		if p.hasDuplicate {
 			appendDuplicatePayment(
 				t, pControl.db, info.PaymentHash,
-				uint64(duplicateSeqNr),
+				uint64(duplicateSeqNr), preimg,
 			)
 			duplicateSeqNr++
 		}