[horizon] missing reviews for cinder backup filtering

Hi folks, We're nearing a very long time that this patch has been open, it's undergone several revisions from our team and sitting idle almost 2 months. https://review.opendev.org/c/openstack/horizon/+/791532/ Can we please help get this landed, we're trying our best to stick to our upstream only :) Thanks Mohammed -- Mohammed Naser VEXXHOST, Inc.