GATK4 conda failures

[matthdsm]

All gatk4 modules were updated in #9033.
However, the PR was force merged @maxulysse, with approval from @nf-core/maintainers with some standing conda issues for the gakt4/createreadcountpanelofnormals module.

This was seemingly caused by an underlying spark dependency, which didn't jive with conda.
Docker/Singularity tests pass without any issues.