Minor performance tweak to handle LuaType casting better if type is already a LuaType

Upsilon/BaseTypes/TypeConversion.cs

@@ -8,6 +8,7 @@ namespace Upsilon.BaseTypes
     {
         public static LuaType ToLuaType(this object o)
         {
+            if (o is LuaType type) return type;
             switch (o)
             {
                 case bool b: