Use algorithm for IsResponsibleForIndex check.

CInterface/Battling/BattleParty.cpp

@@ -19,3 +19,9 @@ export uint8_t CreatureLib_BattleParty_IsResponsibleForIndex(bool& out, const Ba
 }
 
 export bool CreatureLib_BattleParty_HasCreaturesNotInField(const BattleParty* p) { return p->HasCreaturesNotInField(); }
+
+inline bool BattleParty::IsResponsibleForIndex(uint8_t side, uint8_t index) const {
+    return std::any_of(_responsibleIndices.begin(), _responsibleIndices.end(), [side, index](const CreatureIndex& ci) {
+        return ci.GetSideIndex() == side && ci.GetCreatureIndex() == index;
+    });
+}