Container registry: stop appending Root image

...istry/explorer/components/details_page/details_header.vue

...registry/explorer/components/list_page/image_list_row.vue

...egistries/container_registry/explorer/constants/common.js

..._registries/container_registry/explorer/pages/details.vue

locale/gitlab.pot

...y/explorer/components/details_page/details_header_spec.js

...stry/explorer/components/list_page/image_list_row_spec.js

...istries/container_registry/explorer/pages/details_spec.js