refactor: Ran pyupgrade on openedx/core/djangoapps/enrollments (#26912)

openedx/core/djangoapps/enrollments/api.py

openedx/core/djangoapps/enrollments/apps.py

openedx/core/djangoapps/enrollments/data.py

openedx/core/djangoapps/enrollments/errors.py

openedx/core/djangoapps/enrollments/forms.py

...nrollments/management/tests/test_enroll_user_in_course.py

openedx/core/djangoapps/enrollments/serializers.py

openedx/core/djangoapps/enrollments/services.py

openedx/core/djangoapps/enrollments/tests/test_api.py

openedx/core/djangoapps/enrollments/tests/test_data.py

openedx/core/djangoapps/enrollments/tests/test_services.py

openedx/core/djangoapps/enrollments/tests/test_views.py

openedx/core/djangoapps/enrollments/urls.py

openedx/core/djangoapps/enrollments/views.py