Update Wormblight / Take 2: WO Fix

It was pointed out that Writhing One relies on the 'worm' attribute to heal from it's pet's infestation pools and the previous change would have negated that. We restore the check for the attribute to decide healing, but also check the target is an ally. We also move the 'worm' attribute from the sustain to a passive for Reaver's to prevent damage/death from the effect if the sustain is removed.