Exclude some pending or inactivated rows in Member scopes

An unapproved request or not-yet-accepted invite should not give access rights. Neither should a blocked user be considered a member of anything.

One visible outcome of this behaviour is that owners and masters of a group or project may be blocked, yet still receive notification emails for access requests.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/21650

See merge request !1994