Core/Spells: Fix double dipping of healing spells

Stops triggered spells with DAMAGE_CLASS_NONE from gaining double bonuses or deficits from %done and %taken auras on caster/target.
Spells with DAMAGE_CLASS_NONE that are triggered from an aura has to have their healing calculated in their respective spellscripts.
This is not how i intended to fix it in the first way, but due to spells like lifebloom this is the only way.