Steps to reproduce:
1. Install ezplatform-ee-demo, 2.2-test branch (a1ef71cadb980e32b91b1cee1d33458f16bc5344)
2. goto /admin/
3. goto content / content structure (Home - Landing page content type)
4. goto page builder (site siteaccess)
5. goto edit mode
6.1 drag&drop embed block, click on 'configure' icon
6.2 open inspector on network tab
7. put 217 in 'content' field, click submit

expected result: rendered block with working preview
actual result: An exception has been thrown during the rendering of a template ("No view template was set to render the view with the 'block_item' view type. Check your view configuration.").
on /studio/preview/block

potential issue: configuration iframe is reading the views config from admin siteaccess, not site siteaccess

workaround:
app/config.views.yml:

ezpublish:
    system:
        site_group:
            content_view: &SITE_GROUP_CONTENT_VIEW
                ...
        admin_group:
            content_view:
                <<: *SITE_GROUP_CONTENT_VIEW