selftests: openvswitch: add userspace parsing

The userspace action lacks parsing support plus it contains a bug in the
name of one of its attributes.

This patch makes userspace action work.

Reviewed-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
Link: https://patch.msgid.link/20240704085710.353845-9-amorenoz@redhat.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>