refactor: drop /tests package in favor of openedx_authz/tests

Author: mariajgrimaldi

tox.ini

@@ -73,7 +73,6 @@ deps =
     setuptools
     -r{toxinidir}/requirements/quality.txt
 commands =
-    touch tests/__init__.py
     pylint openedx_authz tests test_utils manage.py setup.py
     rm tests/__init__.py
     ruff check openedx_authz tests test_utils manage.py setup.py