The problem needs to be fixed by a complete overhauling of of the openstack-dashboard-ubuntu-theme package. In particular, stuff needs to move from /usr/share/openstack-dashboard-ubuntu-theme to /usr/share/openstack-dashboard/openstack_dashboard/themes/ubuntu. I did the same process for our local theme package, and it worked and did no longer produce the error.
The problem needs to be fixed by a complete overhauling of of the openstack- dashboard- ubuntu- theme package. In particular, stuff needs to move from /usr/share/ openstack- dashboard- ubuntu- theme to /usr/share/ openstack- dashboard/ openstack_ dashboard/ themes/ ubuntu. I did the same process for our local theme package, and it worked and did no longer produce the error.