Added edx-when's FieldData

EDUCATOR-4554
This fixes a bug where extended due dates were visible in the outline but not reflected on the courseware pages, resulting in problems not being submittable past the due date.
In order for edx-when to work on courseware pages, it has to be more careful about field inheritance, which version 0.2 achieves.

lms/djangoapps/courseware/module_render.py

@@ -888,6 +888,7 @@ def get_module_for_descriptor_internal(user, descriptor, student_data, course_id
         system,
         user.id,
         [
+            partial(DateLookupFieldData, course_id=course_id, user=user),
             partial(OverrideFieldData.wrap, user, course),
             partial(LmsFieldData, student_data=student_data),
         ],