Do not allow sync-images job to fail
https://dev.gitlab.org/gitlab/charts/components/images/-/jobs/5911208 failed, but the pipeline was still successful. Hence, it didn't trigger a Slack notification. Let's change that.
https://dev.gitlab.org/gitlab/charts/components/images/-/jobs/5911208 failed, but the pipeline was still successful. Hence, it didn't trigger a Slack notification. Let's change that.