Issue: When trying to duplicate courses with the visibility set to
members we won't be able to duplicate it, since when creating the
duplicate course we won't copy the enroll policy and instead we will
apply the default value, 'open' which triggers our validation error.
Steps to reproduce:
1. Install website_slides.
2. Create a new eLearning course.
3. Set the options:
-Show course to: Course Attendees
-Enroll Policy: On Invitation
4. Try to create a copy of this course.
Solution: If we allow the copy of the enroll policy we will make sure
that the new created course has the right parameters to be created.
opw-3749209
closesodoo/odoo#158651
X-original-commit: f17a3d331f877116271e014c5a7b61938311944c
Signed-off-by: Maruan Aguerdouh Mohtar (magm) <magm@odoo.com>