Roster does not display group membership if user is in only one group

If a user is assigned to one and only one group, the Roster displays nothing where the Group name should be (in either card view or list view)

If a user is assigned to more than one group, it displays correctly – i.e. a dropdown menu appears which lists correct groups.

Steps to replicate:

1. On Sakai 19, in Site Info > Manage Groups, create two groups.
2. Assign some users to one group only. Assign other users to both groups.
3. Go to the Roster view, and select either Card or List layout (i.e. the two layouts that show group membership).
4. Notice that for users assigned to only one group, no group at all is displayed. For users assigned to 2 groups, things display fine – a dropdown appears that lists the correct groups.

Tested on https://qa1-us.nightly.sakaiproject.org using current versions of Firefox and Chrome on Windows 10 (but screenshot is from our local instance)