Core/Units: fixed a typo that was causing units without mana to deal no spell damage anymore

src/server/game/Entities/Unit/Unit.cpp

@@ -6725,7 +6725,7 @@ float Unit::SpellDamagePctDone(Unit* victim, SpellInfo const* spellProto, Damage
     }
 
     // Add SPELL_AURA_MOD_DAMAGE_FROM_MANA percent bonus
-    if (GetPowerIndex(POWER_MANA) != MAX_POWERS)
+    if (HasAuraType(SPELL_AURA_MOD_DAMAGE_FROM_MANA) && GetMaxPower(POWER_MANA))
     {
         float totalBonus = (owner->GetTotalAuraMultiplierByMiscMask(SPELL_AURA_MOD_DAMAGE_FROM_MANA, spellProto->GetSchoolMask()) - 1.f) * 100.f;
         float manaPct = 100.f* ((float)GetPower(POWER_MANA) / GetMaxPower(POWER_MANA));