Stop testing 1.19, start testing 1.23
1.19 ends support now: https://docs.gitlab.com/ee/user/clusters/agent/#supported-cluster-versions
So there's probably no reason to keep providing this image here.
Although, we don't yet support 1.23, as well as not 1.22, I'm proposing to add 1.23 to the utilities just to facilitate start testing it in the other projects that use this tooling.