refactor!: delete common/lib and related usages

.github/workflows/unit-tests.yml

@@ -61,7 +61,7 @@ jobs:
       - name: install requirements
         run: |
           sudo pip install -r requirements/pip.txt
-          sudo pip install --exists-action='w' -r requirements/edx/testing.txt
+          sudo make test-requirements
           if [[ "${{ matrix.django-version }}" == "pinned" ]]; then
             sudo pip install -r requirements/edx/django.txt
           else