Revert "pytest -s"

This reverts commit 2c0f75f.

scripts/run-python-tests.sh

@@ -15,7 +15,7 @@ cd "${amici_path}"/python/tests
 source "${amici_path}"/venv/bin/activate
 
 # PEtab tests are run separately
-pytest -s \
+pytest \
   --ignore-glob=*petab* \
   --ignore-glob=*test_splines.py \
   --durations=10 \