Backport lava: update for session-lock-down-no-deny and apparmor-ofono tests

As defined in test-cases/apparmor-session-lockdown-no-deny.yaml this test doesn't apply for fixedfunction images.

The apparmor ofono test can now be run on OSTree images, but not on fixedfunction images where ofono is not installed.

This backport needs to commits from @em

Signed-off-by: Frédéric Danis frederic.danis@collabora.com