Core/Spells: SPELL_AURA_MOD_HEALING should be negative if TargetType is negative (#24862)

src/server/game/Spells/SpellInfo.cpp

@@ -3714,6 +3714,7 @@ bool _isPositiveEffectImpl(SpellInfo const* spellInfo, uint8 effIndex, std::unor
             case SPELL_AURA_MOD_ATTACKER_RANGED_CRIT_DAMAGE:
             case SPELL_AURA_MOD_ATTACKER_SPELL_AND_WEAPON_CRIT_CHANCE:
             case SPELL_AURA_DUMMY:
+            case SPELL_AURA_MOD_HEALING:
                 // check target for positive and negative spells
                 if (!_isPositiveTarget(spellInfo, effIndex))
                     return false;