Update to new Arbutils memory model.

src/Battling/Library/ExperienceLibrary.cpp

@@ -36,12 +36,12 @@ void PkmnLib::Battling::ExperienceLibrary::HandleExperienceGain(
     }
 
     auto battle = fainted->GetBattle();
-    if (battle == nullptr) {
+    if (!battle.HasValue()) {
         return;
     }
 
     std::unordered_set<CreatureLib::Battling::Creature*> shareExperience;
-    for (const auto& party : battle->GetParties()) {
+    for (const auto& party : battle.GetValue()->GetParties()) {
         for (const auto& mon : party->GetParty()->GetParty()) {
             if (mon == nullptr)
                 continue;