Add test coverage to ensure that all basic starter routes render correct revisions

[lauriii]

We should add test coverage to ensure that both preview and non-preview mode load correct revisions of entities in all routes. This includes individual pages rendered with [..slug].ts and pages that list multiple entities.

The intended behavior is that on preview mode when the user is authenticated, all of the routes should render the latest revision, even if it's not public. When the user is not authenticated, the latest public revision should be rendered instead.