pg_dump: Allow pg_dump to dump the statistics for foreign tables.

pg_dump: Allow pg_dump to dump the statistics for foreign tables.

Commit 1fd1bd87101 introduced support for dumping statistics with
pg_dump and pg_dumpall, covering tables, materialized views, and indexes.
However, it overlooked foreign tables, even though functions like
pg_restore_relation_stats() support them.

This commit fixes that oversight by allowing pg_dump and pg_dumpall
to include statistics for foreign tables.

Author: Fujii Masao <[email protected]>
Reviewed-by: Corey Huinker <[email protected]>
Reviewed-by: Nathan Bossart <[email protected]>
Discussion: https://postgr.es/m/3772e4e4-ef39-4deb-bb76-aa8165f33fb6@oss.nttdata.com