Use group ID and not display name on remove

[fcharlaix-opendsi]

In the login service, group display name and ID are mixed, causing users to be removed and added to the same group when a display name is set.

This problem sends notifications to the user (if enabled) and remove external storage on the desktop client (if external storage are disabled when added, the default behavior in the desktop client configuration).

[pulsejet]

Hmm this isn't super intuitive since it makes impossible to rename groups. Perhaps it might make more sense to exclusively use the display name of the group over the GID

EDIT: the fundamental issue is that the GID isn't very obvious, e.g. in the admin panel unless you look at the URL

EDIT 2: on second thoughts, probably sticking to GID is the best and document this instead.

[pulsejet]

Pls ignore the false alarm. Should be good with 092c223