DB Persistence errors are *too* quiet

Summary: The fix to Changing an object's state in Space.modifyThing() isn't sufficiently atomic has the side-effect that the UI no longer waits for DB modify operations to complete. This is generally an improvement, but means that, in the dreadful case that the DB update fails for some reason, it's rather invisible to the user.

Not actually clear what the correct response here is. DB failures are probably near-fatal, and this should be a truly rare and exceptional situation. But when it happens, we want to nip it in the bud, and we shouldn't lie to the user about the fact that their state wasn't recorded properly.