fix: death call several times (opentibiabr#3186)

fix opentibiabr#3177

Author: mehah

src/creatures/creature.cpp

@@ -711,6 +711,10 @@ std::shared_ptr<Item> Creature::getCorpse(const std::shared_ptr<Creature> &, con
 }
 
 void Creature::changeHealth(int32_t healthChange, bool sendHealthChange /* = true*/) {
+	if (isLifeless()) {
+		return;
+	}
+
 	int32_t oldHealth = health;
 
 	if (healthChange > 0) {

src/creatures/creature.hpp

@@ -209,7 +209,11 @@ class Creature : virtual public Thing, public SharedObject {
 	}
 
 	bool isAlive() const {
-		return !isDead();
+		return !isLifeless();
+	}
+
+	bool isLifeless() const {
+		return health <= 0;
 	}
 
 	virtual int32_t getMaxHealth() const {

src/creatures/monsters/monster.cpp

@@ -1110,7 +1110,7 @@ void Monster::onThink_async() {
 
 void Monster::doAttacking(uint32_t interval) {
 	const auto &attackedCreature = getAttackedCreature();
-	if (!attackedCreature || (isSummon() && attackedCreature.get() == this)) {
+	if (!attackedCreature || attackedCreature->isLifeless() || (isSummon() && attackedCreature.get() == this)) {
 		return;
 	}