Select directories for comparison carefully in the RTW

[ehogan]

The compare_examples--recipe_python job is failing on DKRZ with:

[INFO] rtw-env python ${COMPARE_SCRIPT} ${KGO_DIR} ${COMPARISON_OUTPUT_DIR} --verbose
+ rtw-env python /opt/conda/envs/esmvaltool/lib/python3.12/site-packages/esmvaltool/utils/testing/regression/compare.py /work/bd0854/KGO/esmvaltool_output//recipe_python_20240703_214154 /work/bd0854/KGO/esmvaltool_output//recipe_python_for_CI_20240703_213618 /home/b/b382148/cylc-run/recipe_test_workflow/run12/share/cycle/20241218T1716Z/recipe_python_20241218_171935 --verbose
[INFO] Using the experimental container
Comparing recipe run(s) in:
/work/bd0854/KGO/esmvaltool_output/recipe_python_for_CI_20240703_213618
/home/b/b382148/cylc-run/recipe_test_workflow/run12/share/cycle/20241218T1716Z/recipe_python_20241218_171935
to reference in /work/bd0854/KGO/esmvaltool_output/recipe_python_20240703_214154

recipe_python_for_CI.yml: no reference run found, unable to check

COMPARISON_OUTPUT_DIR must be more specific than ${OUTPUT_DIR}/${RECIPE_NAME}* so that, for example, in this case, recipe_python_for_CI isn't selected in addition to recipe_python.