[sonic-utilities] submodule update (#7201)

9a2872d [cli] Dynamic cli extension via plugins (#1186)
6b51bcd [ci]: add vstest to azure pipeline (#1436)
28b64ec [acl-loader]: do not add default deny rule for egress acl (#1531)

Signed-off-by: Stepan Blyschak <stepanb@nvidia.com>