Change test of Docker archives job

What does this MR do and why?

We're trying to bring the archives image in the gitlab-docs registry and streamline the release process, see gitlab-docs-archives#18.

Instead of building the archives image to test the archives image job, use docker manifest inspect "$image" to query the registry to see if the images are present. We don't need to pull the images to verify the archives job, just making sure they're there is enough.

This will eliminate the somewhat duplicate job (build the archives image twice, one in the test job and one in the actual job), and make the test significantly faster. The archives image build takes over 60 minutes.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Configure a local GitLab Docs environment: https://gitlab.com/gitlab-org/gitlab-docs/-/blob/main/doc/setup.md.
2. Checkout this branch.
3. Run the script and see it succeeding :

   scripts/check-docker-archives.sh

4. To see the script failing, edit archives.Dockerfile and change 13.0 to 17.0.

Merge request acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this merge request.