pgsql: Fix pg_dump ACL minimization for PROPERTY GRAPH.

Fix pg_dump ACL minimization for PROPERTY GRAPH.

Adding a GRANT caused pg_dump to emit a useless REVOKE + GRANT of owner
privileges, as seen in a dump of the regression database:

REVOKE ALL ON PROPERTY GRAPH graph_rls_schema.cabinet FROM nm;
GRANT ALL ON PROPERTY GRAPH graph_rls_schema.cabinet TO nm;
GRANT ALL ON PROPERTY GRAPH graph_rls_schema.cabinet TO PUBLIC;

For normal dumps, this has no functional consequences. For --no-owner
restores, the extra statements may fail or locate unrelated users of the
destination cluster.

The problem was pg_dump assuming NULL relacl implies acldefault('r'),
the default for TABLE. Fix by teaching acldefault() to retrieve the
PROPERTY GRAPH default ACL. So pg_dump can still dump from 19beta1, use
acldefault('g') for v20+ only. For v19, use a hard-coded snapshot of
the v19 default.

information_schema.pg_property_graph_privileges also misused
acldefault('r'), but its "c.prtype IN ('SELECT')" predicate compensated
for it. Switch to the new acldefault('g') for clarity. Bump catversion
since a new view won't work with old binaries. Back-patch to v19, which
introduced PROPERTY GRAPH.

Reviewed-by: Ashutosh Bapat <ashutosh(dot)bapat(dot)oss(at)gmail(dot)com>
Reviewed-by: Robert Haas <robertmhaas(at)gmail(dot)com>
Discussion: https://postgr.es/m/20260630023308.c7.noahmisch@microsoft.com
Backpatch-through: 19

Branch
------
REL_19_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/ccca2cd81b2dab2be7d9d451a84d971a8489ca70

Modified Files
--------------
src/backend/catalog/information_schema.sql | 2 +-
src/backend/utils/adt/acl.c | 3 +++
src/bin/pg_dump/pg_dump.c | 37 +++++++++++++++++++++++++++---
src/include/catalog/catversion.h | 2 +-
4 files changed, 39 insertions(+), 5 deletions(-)