WIP: Test stories and components colocation in gitlab-ui

What does this MR do?

This MR's purpose is to make sure that the new files structure in gitlab-ui!245 (merged) won't break any component imports.

The package.json and yarn.lock have been updated to use the corresponding artifact: https://gitlab.com/gitlab-org/gitlab-ui/-/jobs/204411119/artifacts/raw/gitlab-ui.215-colocate-stories-components.tgz

If all goes well (relevant tests green in the pipeline) and gitlab-ui!245 (merged) is merged, this MR will be closed and @gitlab/ui will be updated via renovate-bot.