Fix update manager automated report

The update manager tests report the different phases as aum-*-phase-[1..x]. This is does not cope with the qa reporting tool that expects a result with the same name than the test yaml definition. Let's consider the last phase of the test to be the final result. Any previous error would have been carried forward.

Signed-off-by: Frédéric Dalleau frederic.dalleau@collabora.com

Test job: https://lava.collabora.co.uk/scheduler/job/1557153