Fix potential error message in retrigger job
TypeError: 'NoneType' object is not subscriptable Example: https://git.seco.com/seco-ne/yocto/infrastructure/ci-test/minimal-manifest/-/jobs/127610
TypeError: 'NoneType' object is not subscriptable Example: https://git.seco.com/seco-ne/yocto/infrastructure/ci-test/minimal-manifest/-/jobs/127610