EDIT This was wrong
I think that playlists are supposed to be viewable by Managed users because you can choose them in the options of https://support.plex.tv/articles/manage-recommendations/
However I can’t get them to show up either. What I found when testing this on an iPad is that iOS places the admin’s playlists in a section called Shared
So on my iOS Plex App sidebar, I have pinned
Home
Movies
TV Shows
Playlists
Shared
More >
Playlists from Admin are empty for managed user, but Shared contains them.
I’m not sure if this is intended 
Below is the right one.
