This should theoretically not be possible, but while we are sharing this
control's implementation between gameplay and non-gameplay usages, let's
ensure nothing weird can occur.
This is an interesting scenario where we arrive at a fresh
`BeatmapOffsetControl` but with a reference score (from the last play).
Our best assumption here is that the beatmap's offset hasn't changed
since the last play, so we want to use it for the `lastPlayBeatmapOffset`.
But due to unfortunate order of execution, `Current.Value` was not yet
initialised.