Provide option to choose showing full names in chat

[davidb]

This feature has now been added:

FEATURE: allow names in chat channel title (#28843)

Note that for users that don’t have a name on their profile, it will revert to the username for those individual users.

To get this working, it requires the same settings outlined here:

@Lilly

in admin - settings, you need to have enable_names and display_name_on_posts enabled (checked) and then make sure prioritize_username_in_ux is disabled (unchecked).