Some AD edge-case causes missing members

Zendesk: https://gitlab.zendesk.com/agent/tickets/19862

A seemingly edge-case in AD causes the recursive member of search to return only a few actual group members. Running a normal group search and using the member attribute yields correct results (of course, without recursive members).

@jacobvosmaer suggests to do both the recursive search and merge with regular members to overcome this. Seems reasonable so I will pursue that fix.