Fix offset adjust control not correctly applying changes after song s…

…elect quit

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.

osu.Game/Screens/Play/PlayerSettings/BeatmapOffsetControl.cs

@@ -104,8 +104,6 @@ protected override void LoadComplete()
         {
             base.LoadComplete();
 
-            ReferenceScore.BindValueChanged(scoreChanged, true);
-
             beatmapOffsetSubscription = realm.SubscribeToPropertyChanged(
                 r => r.Find<BeatmapInfo>(beatmap.Value.BeatmapInfo.ID)?.UserSettings,
                 settings => settings.Offset,
@@ -124,6 +122,7 @@ protected override void LoadComplete()
                 });
 
             Current.BindValueChanged(currentChanged);
+            ReferenceScore.BindValueChanged(scoreChanged, true);
         }
 
         private void currentChanged(ValueChangedEvent<double> offset)