[Port dspace-8_x] [Docker] Fix bug in docker-deploy test by always pulling backend image from docker.io#5017

tdonohue merged 1 commit intodspace-8_xDSpace/dspace-angular:dspace-8_xfrom

backport-5016-to-dspace-8_xDSpace/dspace-angular:backport-5016-to-dspace-8_xCopy head branch name to clipboard