Deleting a hold leaves lingering moves in the UI

[LucasPickering]

If you delete a hold that haves moves on it, then the hold disappears but the moves still show in the UI until you refresh the page.

This is because the deleteHold mutation only returns the deleted hold, which we can purge from Relay, but it doesn't return any info about the deleted moves, because those are deleted implicitly by the DB due to cascading.

This will be a bit of a pain to fix, so I'm ignoring it for now because I don't expect it to be a common scenario. If you've gotten far enough along to start adding beta, then the tagged hold is probably legit and won't need to be deleted.