qa/suites: drop --show-reachable=yes from fs:valgrind tests

qa/suites: drop --show-reachable=yes from fs:valgrind tests

Drop --show-reachable=yes from fs:valgrind tests as it shows CommandFailedError,
which fails starting cephfs-mirror daemon and prevents the valgrind checks and reports.
rbd:valgrind tests doesn't use --show-reachable=yes too.
So dropping --show-reachable=yes to make it analogous to rbd:valgrind.

Fixes: https://tracker.ceph.com/issues/64752
Fixes: https://tracker.ceph.com/issues/62221
Signed-off-by: Jos Collin <jcollin@redhat.com>
(cherry picked from commit f17f2d6fee1dc59958678b697a0e0319c34691a7)