Allow pg_read_all_stats to read replication origin status

Hi,

I have been looking at the requirement for providing non-superuser
read access to specific catalog relations, specifically
pg_replication_origin_status. During this, I reviewed the capabilities
of the pg_read_all_stats role.

Looks like pg_read_all_stats was originally designed to grant access
to all pg_stats_* views, a few other monitoring views defined in
system_views.sql have been included over time. However, access to
pg_replication_origin_status remains restricted and is not currently
covered by existing roles such as pg_read_all_stats, pg_read_all_data,
or pg_monitor.

The attached patch grants pg_read_all_stats read access to the
pg_replication_origin_status view and its underlying function,
consistent with the existing approach for monitoring views in
system_views.sql. I have also included the relevant regression tests.

On pgsql-hackers, I noted a previous discussion [1] regarding granting
this access; however, that discussion focused on the pg_monitor role
rather than pg_read_all_stats and never got commited.

[1] https://www.postgresql.org/message-id/flat/CAPdiE1zUeSycQ-VHrZQMDR4vkPthYTSxeQPXM-ZfH8QHDBCE%3DQ%40mail.gmail.com

Thanks,
Virender