Change advertising auto-refill (website only; not offered)

Auto-refill is not offered under the current Advertiser Terms: this returns 409 auto_refill_not_offered unless updated terms that offer it are published and enabled. When offered, turning it on needs its own consent (threshold, refill amount, monthly refill limit) and a card saved through an advertising top-up. Website only: requests from the mobile apps are refused with 403 web_only_action. Only the business's human owner can do this: agent credentials are refused with 403 ads_owner_action_required, and a fresh second factor is required (403 owner_step_up_required).