Using standard licensed image to make a gift for friend

The license terms say, that if the asset is the main incentive for the buyer (of the item)  then you will need to take an extended licence. For a mug, that would be true. For postcards or similar, that would be true too. I understand that your giftcard is borderline, and it may flipp in one or the other category. 

However, I would consider the gift (amount) to be the main part. And as I understand it, you really look into a unique use and not giftcards for sale, where you can choose between dozends of cards and the asset will decide which one yo buy.

I've used stock assets on custom made invitation cards, which I consider equivalent to your use, and I've used a standard licence for that. If I would sell that design printed on a card, I would need an extended licence.

Look here for more information on licensing: https://community.adobe.com/t5/stock/links-for-licensing-terms/td-p/11366788
(Disclaimer: As always with licensing, this is my interpretation of the rules. I think they are correct and advice is based on reading and interpreting the licence terms and on fair use for both the buyer and the artist/stock company, but I cannot rule out that my interpretation is wrong. I'm not an Adobe employee).