Make tests on MR manual jobs

The idea behind tests on MR is to catch issues on new versions before they land to the main archives. In the context of system packages like rust-coreutils, linux, systemd and apertis-update-manager it is very useful to excercise the whole image pipeline, to test that images will be able to build and also to run LAVA tests on those images.

However, this exercise is very expensive, and has little sense on trivial changes, like license scan updates, documentation updates or even small patches.

To overcome this problem change the test job to become a manual one, letting the developer or the reviewer the decision of exercise the full image pipeline and test it or not.

Signed-off-by: Walter Lozano walter.lozano@collabora.com