Not sure on the future of this, but given it is used in the
save-failed-reply pull request (#18785) I think it's fine to add back
for now.
Without this, JSON parsing of older scores in server-side storage will
fail on missing enum type.
Really this shouldn't happen but I managed to make it happen. Until this
comes up again in a way that matters, let's just fix the LINQ crash from
`SingleOrDefault`.
I've tested this to work as expected in the broken scenario.