Remove python3-mock from the tests

The mock library has been integrated in Python 3 standard library,
it's now unittest.mock.

Resolves: rhbz#1922326

tests/tests.yml

@@ -10,7 +10,6 @@
     - classic
     required_packages:
     - "python3-pytest"
-    - "python3-mock"
     - "anaconda"
     tests:
     - smoke:
@@ -22,7 +21,6 @@
     - classic
     required_packages:
     - "python3-pytest"  # Not needed for this test, it is just a temp workaround for an Ansible bug https://github.com/ansible/ansible/issues/57365
-    - "python3-mock"  # Not needed for this test, it is just a temp workaround for an Ansible bug https://github.com/ansible/ansible/issues/57365
     - "anaconda"
     tests:
     - Sanity/dir-install: