qa/tasks/workunit: fix no module named 'pipes'

Python 3.13 finally dropped the 'pipes' module,
replacing it with shlex.

Fixes: https://tracker.ceph.com/issues/73498
Signed-off-by: Kyr Shatskyy <kyrylo.shatskyy@clyso.com>
(cherry picked from commit da40484b9577aba21833e6b09c6129fe2d3c596c)

Merge pull request #65584 from rzarzynski/wip-bug-72412-squid

squid: osd: stop scrub_purged_snaps() from ignoring osd_beacon_report_interval

Reviewed-by: Prashant D <pdhange@redhat.com>