Do not show (zero) size of container registry manifest lists/indexes in the UI

Context

Part of Improve container registry multi-architecture i... (&11952).

Problem

After the fixes introduced in Manifest lists/multi-arch images are not displa... (&10434 - closed), and more precisely Use the list repository tags API and its pagina... (#411387 - closed), we can now see the size of manifest lists/indexes in the UI.

Using the below screenshot from https://gitlab.com/jdrpereira/multi-arch/container_registry/1245177...

We can see that the size of the image with tag 1.0.0 is zero bytes. This is because this image is an OCI index, and more precisely a multi-architecture image. As such, this image has no directly associated layers. Instead, it's an index that only references the actual platform specific images (the ones with assigned layers, and therefore with a non-zero size), which in this case are 1.0.0-amd64 and 1.0.0-arm64v8.

Therefore, showing a size of zero for manifest lists/indexes is unnecessary.

Implementation guide

We can hide this field in the UI when a given tag is flagged as a list/index (depends on #408865 (closed)) and the size is zero.

The tag is list/index if mediaType on is one of application/vnd.docker.distribution.manifest.list.v2+json (Docker) or application/vnd.oci.image.index.v1+json (OCI).

• Add mediaType query to app/assets/javascripts/packages_and_registries/container_registry/explorer/graphql/queries/get_container_repository_tags.query.graphql
• Update app/assets/javascripts/packages_and_registries/container_registry/explorer/components/details_page/tags_list_row.vue to handle value & hide size.