feat: OnAttack behavior (#1853)

Adds the `OnAttack` property behavior starting node.
Tested that having the node allows the model to be attacked to trigger the start of behaviors

dGame/dGameMessages/GameMessages.h

@@ -863,5 +863,13 @@ namespace GameMessages {
 
 		NiPoint3 pos{};
 	};
+
+	struct SetFaction : public GameMsg {
+		SetFaction() : GameMsg(MessageType::Game::SET_FACTION) {}
+
+		int32_t factionID{};
+
+		bool bIgnoreChecks{ false };
+	};
 };
 #endif // GAMEMESSAGES_H