crimson/osd: skip PGAdvanceMap on a deleted PG

crimson/osd: skip PGAdvanceMap on a deleted PG

A PGAdvanceMap queued by broadcast_map_to_pgs can sit behind in-flight
DeleteSome events on the peering pipeline holding a Ref<PG>.  When it
finally runs, the collection has already been removed in seastore and
PGAdvanceMap drives handle_advance_map / check_for_splits on a stale
PG thereby issuing ops on a collection that no longer exists, crashing the OSD.

Following Classic OSD, set peering_state.set_delete_complete() in PG::do_delete_work's
final batch and bail out of PGAdvanceMap::start when pg->is_deleted() is true.

Fixes: https://tracker.ceph.com/issues/76447
Signed-off-by: Aishwarya Mathuria <amathuri@redhat.com>