gitlab-ci: Fix aum tests generation

generate-jobs.py doesn't create the aum tests with the following message:

template variable not defined in aum-ota-out-of-space: 'image_bundle' is undefined

This variable needs to be set in template-submit-tests.yml

https://phabricator.apertis.org/T8487

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