`autotailor-unit-tests` unit test runs when pytest is not installed

[mildas]

Description of Problem:

During ctest, autotailor test runs even when pytest is not installed on a system. As it is not openscap requirement, it should be optional and run only when pytest is installed.

OpenSCAP Version:

1.4.0

Operating System & Version:

RHEL 10

Steps to Reproduce:

1. ctest --force-new-ctest-process --output-on-failure

Actual Results:

276/277 Test #276: autotailor-unit-tests ..............................................................***Failed    0.01 sec
/usr/bin/python3: No module named pytest

Expected Results:

276/277 Test #276: autotailor-unit-tests ..............................................................***Skipped    0.01 sec

Additional Information / Debugging Steps:

if(PY_PYTEST) conditon for https://github.com/OpenSCAP/openscap/blob/main/tests/utils/CMakeLists.txt should ensure that