Add support for creating pokemon with passed Random parameter.

src/Battling/Pokemon/CreatePokemon.hpp

@@ -67,7 +67,11 @@ namespace PkmnLib::Battling {
         CreatePokemon& WithNature(const ArbUt::StringView& nature);
         CreatePokemon& IsAllowedExperienceGain(bool value);
 
-        Pokemon* Build();
+        Pokemon* Build() {
+            auto rand = ArbUt::Random();
+            return Build(rand);
+        }
+        Pokemon* Build(ArbUt::Random& rand);
     };
 }