Calling settings_data.user_can_access_all_other_users on every call to
this function could be expensive when using this function in loops
over every user in the organization.
After the previous commit, those calls are still somewhat expensive
for guest users.
Opening settings and stream settings UI was not working for guests
if they could not access all users. This was because is_person_active
did not handle inaccessible users correctly, if they were not added in
the users data, when being called in get_group_members to render
group pills.
