Coupon restrictions by brand are not supported

[nicdwilson]

Describe the bug:

While coupon restrictions by brand were previously only available to merchants running a brands plugin, this situation now changes with the introduction of brands to core WooCommerce. In 9069070-zd-a8c the merchant reached out to understand why brand restrictions were not being honored in the coupon field.

We map coupon restrictions here with no mention of brands.

Not sure if this is a bug or a feature request :)

I lean to bug since this was the user experience.

[ianlin]

@nicdwilson Thanks for reporting this issue, it has been fixed in #2697 and will be released in 2.9.2 (scheduled next Tuesday 10 Dec).