pg_createsubscriber: Fix incorrect handling of cleanup flags

Hi Hackers,

In pg_createsubscriber, the flags 'made_publication' and
'made_replslot' are used to track whether the tool itself created a
publication or replication slot on the primary (publisher) node. If a
failure happens during the process, these flags help the tool decide
whether it should clean up those objects using
cleanup_objects_atexit().
However, there are cases where these flags are wrongly set to false
due to failures on the subscriber side, which causes the tool to skip
cleanup of some objects on the primary even when it should not.

Example: for made_publication
  In drop_publication(), if dropping a publication on the subscriber
fails (either a replicated publication or an existing one being
removed with --remove=publications), the made_publication flag is
wrongly set to false.
The process continues without exiting, but if a later step fails,
cleanup_objects_atexit() will see made_publication = false and skip
dropping the publication on the primary, even though it was created
earlier by the tool. This leads to orphaned publication.

Example: for made_replslot
  A similar issue exists for replication slots. In
drop_replication_slot(), if dropping a physical replication slot on
the primary, or a failover-synced slot on the subscriber, fails — the
made_replslot flag is set to false.
Again, if the process fails later, cleanup_objects_atexit() will
incorrectly skip dropping the logical replication slot created earlier
on the primary, leaving it behind.

Solution:
  The fix ensures that failures in dropping subscriber-side or
non-internal objects should not reset made_publication or
made_replslot.
These flags should only be reset if dropping the internally created
objects on the primary fails. That way, cleanup_objects_atexit() can
still correctly clean up what the tool created if something else goes
wrong later in the process.

Attached is the patch implementing the above proposed solution.
Reviews and feedback are most welcome.

--
Thanks,
Nisha