I'm not sure whether the fix belongs in the charm or the package. We could remove the rendered charm files from /usr/share/openstack-dashboard/openstack_dashboard prior to upgrading. Another option is the package could forcefully remove /usr/share/openstack-dashboard/openstack_dashboard in the preinst script for rocky. The latter might make sense since it's not much different from removing the alternative in the prerm/postrm scripts.
I'm not sure whether the fix belongs in the charm or the package. We could remove the rendered charm files from /usr/share/ openstack- dashboard/ openstack_ dashboard prior to upgrading. Another option is the package could forcefully remove /usr/share/ openstack- dashboard/ openstack_ dashboard in the preinst script for rocky. The latter might make sense since it's not much different from removing the alternative in the prerm/postrm scripts.