Re-enable the signed-off-by job in CI

redhat/scripts/ci/sign_off_check.py has a little script to check patches in a merge request for signed-off-by tags from the author, but all our scripts are generating patches (like the config patches) without signoffs so the CI fails for pretty much everything. We either need to add an exception to the CI script or alter the patch generation scripts to sign off the patches. However, who exactly is responsible for agreeing to the DCO on behalf of the script is odd to think about (the author?) so maybe an exception is better.