cleanup: fix pytest warnings

[AntoinePrv]

No description provided.

[Hind-M]

I don't know exactly what were these pytest warnings, but there are still some remaining teardown functions in some micromamba tests:

micromamba/tests/test_constructor.py:74:    def teardown(cls):
micromamba/tests/test_pkg_cache.py:87:    def teardown(cls):
micromamba/tests/test_pkg_cache.py:291:    def teardown(cls):
micromamba/tests/test_linking.py:42:    def teardown(cls):
micromamba/tests/test_info.py:41:    def teardown(cls):