This commit replaces all the instances where the WPCS rule `WordPress.VIP.SlowDBQuery` was used with `WordPress.DB.SlowDBQuery`. `WordPress.VIP.SlowDBQuery` was deprecated in WPCS 2.0 and `WordPress.DB.SlowDBQuery` was added as a replacement (see 5f27d8e3a4/CHANGELOG.md (L130)).
Makes it more user-friendly for someone unfamiliar with WordPress/WooCommerce, and even for those who are familiar and don’t immediately see the typical “Add Coupon” button in the top left corner by the header.