Commit ad600bba added psql command \dX listing extended statistics
objects, but it failed to consider search_path when selecting the
elements so some of the returned elements might be invisible.

The visibility was already considered for tab completion (added by
commit d99d58cd), so adding it to the query is fairly simple.

Reported and fix by Justin Pryzby, regression tests by me. Backpatch
to PostgreSQL 14, where \dX was introduced.

Batchpatch-through: 14
Author: Justin Pryzby
Reviewed-by: Tatsuro Yamada
Discussion: https://postgr.es/m/c027a541-5856-75a5-0868-341301e1624b%40nttcom.co.jp_1