qa/cephfs: ignore warning that pg is stuck peering for upgrade jobs

qa/cephfs: ignore warning that pg is stuck peering for upgrade jobs

Health warning "pg .* is stuck peering" is seen while Ceph cluster is
under the upgrade process during fs/upgrade QA job. Being an expected
warning, it should be added to the ignorelist.

And besides this one, we already ignore more severe warnings ("pg is
stuck inactive" and "pg is degrarded") for fs/upgrade jobs.

Fixes: https://tracker.ceph.com/issues/70023
Signed-off-by: Rishabh Dave <ridave@redhat.com>