refactor: update to use Learning Core's new public API

This also bumps our openedx-learning dependency to 0.10.0 (the first
version with the new openedx_learning.api package).

setup.cfg

@@ -62,6 +62,7 @@ root_packages =
     lms
     cms
     openedx
+    openedx_learning
 include_external_packages = True
 contract_types =
     # Our custom contract which checks that we're only importing from 'api.py'
@@ -185,3 +186,14 @@ allowed_modules =
     # Only imports from api.py are allowed elsewhere in the code
     # See https://open-edx-proposals.readthedocs.io/en/latest/best-practices/oep-0049-django-app-patterns.html#api-py
     api
+
+[importlinter:contract:3]
+name = Do not import apps from openedx-learning (only import from openedx_learning.api.* and openedx_learning.lib.*).
+type = forbidden
+source_modules =
+    cms
+    lms
+    openedx
+forbidden_modules =
+    openedx_learning.apps
+allow_indirect_imports = True