Do not create tasks for Work In Progress branches

With the switch to GitLab the image building pipeline is building images for work-in-progress branches and submitting them to LAVA.

We're now creating tasks for failures on those WIP branches as well, but it only adds noise on the bugtracker.

Skip the Phabricator updates on tests submitted from wip/* branches.

See also tests/apertis-test-cases!161 (merged)