We do not fetch all the realm group settings using
select_related for register data now since it takes a
lot of time in planning phase. This commit updates
the code to fetch all the members and subgroups data
in user_groups_in_realm_serialized so that we do not
need to access each setting group individually.
user_groups_in_realm_serialized is updated to send the
required data accordingly.
Fixes#33656.
c2f1b3673e