`TestSceneRealtimeReadyButton` was manually adding `API.LocalUser`,
which wasn't actually needed. The base `RealtimeMultiplayerTestScene` by
default creates a new room as `API.LocalUser`, therefore automatically
adding that user to the room - and as such there is no need to add them
manually unless the `joinRoom` ctor param is specified as `false`.
`RNG.Next(int, int)` is max-exclusive, so the random state choice would
actually never pick `MultiplayerUserState.Results` on its own. The only
reason why that state ever did show up was by a freak accident of sorts
(the logic in `TestRealtimeMultiplayerClient` would automatically
convert every `FinishedPlay` state to `Results`, up until seeing the
first player that was in the `Playing` state).
