For get and filter queries of NamedUserGroup, realm_for_sharding
field is used instead of realm field, as directly using
realm_for_sharding field on NamedUserGroup makes the query faster
than using realm present on the base UserGroup table.
This commit updates check_channel_privacy_update to use
do_change_stream_permission for setting the stream privacy
to its old state so that we do that in a reliable way and
can avoid bugs in future.
This commit updates how we check permission for updating
properties of an unsubscribed private channel.
There is no need of checking all can_administer_channel_group
values for unsubscribed private channel, when we check them
for a subscribed private channel. It is sufficient to check
one case where an unsubscribed user can update private channel
if they belong to can_administer_channel_group.
This also helps in avoiding repeated calls to subscribed_to_stream
which made a DB query that could make the test slow.
This commit updates check_channel_property_update to just
accept error_msg parameter instead of having both allow_fail
and error_msg, as error_msg is sufficient to determine
whether the request is expected to fail or not.
