Core/Creatures: Minor HasSpell method cleanup

Cherry-picked improved from 5734788c0277d7f342d534dca63db0ce4e862bc5

src/server/game/Entities/Creature/Creature.cpp

@@ -2391,11 +2391,7 @@ void Creature::SetInCombatWithZone()
 
 bool Creature::HasSpell(uint32 spellID) const
 {
-    uint8 i;
-    for (i = 0; i < MAX_CREATURE_SPELLS; ++i)
-        if (spellID == m_spells[i])
-            break;
-    return i < MAX_CREATURE_SPELLS;                         //broke before end of iteration of known spells
+    return std::find(std::begin(m_spells), std::end(m_spells), spellID) != std::end(m_spells);
 }
 
 time_t Creature::GetRespawnTimeEx() const