square.onGiftCardCustomerUnlinked subscribes to gift_card.customer_unlinked for the selected seller. It requires GIFTCARDS_READ.
Example
automations/square-on-gift-card-customer-unlinked.automation.ts
Event
A customer was unlinked from a gift card. The signal resolves to the officialSquare.GiftCardCustomerUnlinkedEvent payload with type narrowed to gift_card.customer_unlinked.