Certificate Display Settings revamp (round 2) (#28286)

feat: reimagine certificate display settings

The course settings `certificate_available_date` (CAD) and
`certificates_display_behavior` (CDB) were previously
acting indedependantly of one another. They now work in
tandem. This change:
- limits CDB to a dropdown
- removes "early_with_info" and adds "end_with_date"
- only takes CAD into account if "end_with_date" is selected
- Moves CDB to the main course schedule settings page
- updates CourseOverview model and CourseDetails objects to
validate these fields and choose sane defaults if they aren't
expected values

This work was previously done in bd9e7dd (complete with bugs), so this
version is toggleable via the ENABLE_V2_CERT_DISPLAY_SETTINGS setting

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

@@ -2,7 +2,7 @@
 Tests for courseware API
 """
 import unittest
-from datetime import datetime
+from datetime import datetime, timedelta
 from urllib.parse import urlencode
 from typing import Optional
 
@@ -39,6 +39,7 @@ from common.djangoapps.student.roles import CourseInstructorRole
 from common.djangoapps.student.tests.factories import CourseEnrollmentCelebrationFactory, UserFactory
 from openedx.core.djangoapps.agreements.api import create_integrity_signature
 from openedx.core.djangoapps.agreements.toggles import ENABLE_INTEGRITY_SIGNATURE
+from xmodule.data import CertificatesDisplayBehaviors
 from xmodule.modulestore.django import modulestore
 from xmodule.modulestore.tests.django_utils import TEST_DATA_SPLIT_MODULESTORE, SharedModuleStoreTestCase
 from xmodule.modulestore.tests.factories import ItemFactory, ToyCourseFactory
@@ -46,6 +47,8 @@ from xmodule.modulestore.tests.factories import ItemFactory, ToyCourseFactory
 
 User = get_user_model()
 
+_NEXT_WEEK = datetime.now() + timedelta(days=7)
+
 
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class BaseCoursewareTests(SharedModuleStoreTestCase):
@@ -64,6 +67,8 @@ class BaseCoursewareTests(SharedModuleStoreTestCase):
             enrollment_end=datetime(2028, 1, 1, 1, 1, 1),
             emit_signals=True,
             modulestore=cls.store,
+            certificate_available_date=_NEXT_WEEK,
+            certificates_display_behavior=CertificatesDisplayBehaviors.END_WITH_DATE
         )
         cls.chapter = ItemFactory(parent=cls.course, category='chapter')
         cls.sequence = ItemFactory(parent=cls.chapter, category='sequential', display_name='sequence')