Add ExpandNumberPiece configuration with OsuLegacySkinTransformer

osu.Game.Rulesets.Osu/Skinning/OsuLegacySkinTransformer.cs

@@ -123,6 +123,10 @@ public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup)
                                 return SkinUtils.As<TValue>(new BindableFloat(legacy_circle_radius));
 
                             break;
+
+                        case OsuSkinConfiguration.ExpandNumberPiece:
+                            string legacyVersion = source.GetConfig<string, string>("Version")?.Value ?? "1";
+                            return SkinUtils.As<TValue>(new BindableBool(double.TryParse(legacyVersion, out double version) && version < 2.0));
                     }
 
                     break;

osu.Game.Rulesets.Osu/Skinning/OsuSkinConfiguration.cs

@@ -7,6 +7,7 @@ public enum OsuSkinConfiguration
     {
         HitCirclePrefix,
         HitCircleOverlap,
+        ExpandNumberPiece,
         SliderBorderSize,
         SliderPathRadius,
         AllowSliderBallTint,