Use ambient setting of potion effects. Fixes BUKKIT-4357 and BUKKIT-3653

This changes livingEntity.addPotionEffect(PotionEffect, boolean) to
construct the MobEffect using the constructor that includes the ambient
setting as supplied by the PotionEffect

This also changes livingEntity.getActivePotionEffects() to construct the
PotionEffects using the ambient setting supplied by the MobEffects.