[Bug Fix] DI/Death Pact Fix (#3867)

* [Bug Fix] DI/Death Pact Fix

Divine Intervention/Death Pact buffs were always fading the moment a person dropped below 16% regardless if it healed or not.  It will now only fade if it succeeds in healing, and it will only check to heal when a person drops below 16%

* Requested Updates

zone/attack.cpp

@@ -3810,6 +3810,8 @@ void Mob::CommonDamage(Mob* attacker, int64 &damage, const uint16 spell_id, cons
 
 	if (damage > 0) {
 		//if there is some damage being done and theres an attacker involved
+		int previous_hp_ratio = GetHPRatio();
+
 		if (attacker) {
 			// if spell is lifetap add hp to the caster
 			if (IsValidSpell(spell_id) && IsLifetapSpell(spell_id)) {
@@ -4035,8 +4037,9 @@ void Mob::CommonDamage(Mob* attacker, int64 &damage, const uint16 spell_id, cons
 			}
 		}
 		else {
-			if (GetHPRatio() < 16)
+			if (GetHPRatio() < 16 && previous_hp_ratio >= 16) {
 				TryDeathSave();
+			}
 		}
 
 		TryTriggerOnCastRequirement();