cleanup singularity test command in new_model.yml and update_model.yml about trained-models

[hvgazula]

The suggested cleaner version is

singularity exec --nv ./${{ needs.create_new_branch.outputs.MODELPATH }}/docker/${{ needs.build-docker.outputs.MODELNAME }}.sif ${{ needs.create_new_branch.outputs.TESTCOMMAND }}

@gaiborjosue While I am very sure that this suggestion won't fail, if you don't mind, could you please test it for me?

[gaiborjosue]

Hello @hvgazula, sure I will test it.