journal-file: fix archiving offline journals

journal-file: fix archiving offline journals

The existing set_offline() short-circuit erroneously included
when f->archive was true and header->state was STATE_OFFLINE.

This commit makes the short-circuit f->archive aware, so it will
only catch scenarios where there's not an offlining in progress
and the header state matches the target state of either archived
or offline.

Fixes https://github.com/systemd/systemd/issues/17770

(cherry picked from commit bb1296b55a222cbab24d533006e730529009258c)