Add java 11 to conda_setup_script.

Figured on repos/structured-data/image-suggestions!6 (merged) that having Java available in the /gitlab_ci_templates/pipelines/conda_artifact_repo.yml workflow is useful since tests that cover Spark code need a JVM.

It looks like there was an attempt to add Java 8 before, and I found all kinds of problems to install it on Debian buster as well. Here I add Java 11, which I acknowledge is not the same as prod, but at least we can run tests.