Core/Auras: Use existing aura object on aura reapply/stack increase instead of creating a new one.

You can hook on reapply/stack event by checking for AURA_EFFECT_HANDLE_REAPPLY aura handler mode, AURA_EFFECT_HANDLE_REAL is now not triggered on aura refresh/stack.

src/server/scripts/Spells/spell_item.cpp

@@ -722,9 +722,6 @@ public:
         void OnRemove(AuraEffect const* /*aurEff*/, AuraEffectHandleModes /*mode*/)
         {
             Unit* target = GetTarget();
-
-            if (GetTargetApplication()->GetRemoveMode() == AURA_REMOVE_BY_STACK)
-                return;
             target->RemoveAurasDueToSpell(SPELL_SHADOWMOURNE_VISUAL_LOW);
             target->RemoveAurasDueToSpell(SPELL_SHADOWMOURNE_VISUAL_HIGH);
         }