🐛 Unregistered users appear as agent on a public doc

[virgile-dev]

Bug Report

Problematic behavior
When a doc is public, registered or unregistered users when they select some text, their name tag appears for doc editors.
As they do not have any specific right on the doc they should just read and not be considered as agents. Their name tag / the anonymous tag shouldn't appear.
For a public that is public and read by many people this is problematic as nametags would appear on many places in the doc.

Expected behavior/code
Do not show cursor and nametag of users that do not have specific rights on the document.