consolidate ENABLE_FORUM_DAILY_DIGEST config (#24423)

The ENABLE_FORUM_DAILY_DIGEST config was using both
a Django Setting and a waffle flag. This consolidates
this to simply use the single Django Setting:
FEATURES['ENABLE_FORUM_DAILY_DIGEST'].

ARCHBOM-132

lms/djangoapps/discussion/config/settings.py

@@ -0,0 +1,22 @@
+"""
+Discussion settings.
+"""
+from django.conf import settings
+
+# .. toggle_name: FEATURES['ENABLE_FORUM_DAILY_DIGEST']
+# .. toggle_implementation: DjangoSetting
+# .. toggle_default: True
+# .. toggle_description: Set to True to enable forum notification features.
+# .. toggle_category: discussion
+# .. toggle_use_cases: open_edx
+# .. toggle_creation_date: 2020-03-09
+# .. toggle_expiration_date: None
+# .. toggle_tickets: None
+# .. toggle_status: supported
+# .. toggle_warnings: None
+ENABLE_FORUM_DAILY_DIGEST = 'enable_forum_daily_digest'
+
+
+def is_forum_daily_digest_enabled():
+    """Returns whether forum notification features should be visible"""
+    return settings.FEATURES.get('ENABLE_FORUM_DAILY_DIGEST')

lms/djangoapps/discussion/config/waffle.py

@@ -1,27 +0,0 @@
-"""
-Discussion settings and flags.
-"""
-
-from openedx.core.djangoapps.waffle_utils import WaffleFlag, WaffleFlagNamespace
-
-ENABLE_FORUM_DAILY_DIGEST = 'enable_forum_daily_digest'
-
-
-def waffle_flags():
-    """
-    Returns the namespaced, cached, audited Waffle flags dictionary for Grades.
-    """
-    namespace = WaffleFlagNamespace(name='edx_discussions')
-    return {
-        # By default, enable forum notifications. Can be disabled platform wide.
-        ENABLE_FORUM_DAILY_DIGEST: WaffleFlag(
-            namespace,
-            ENABLE_FORUM_DAILY_DIGEST,
-            flag_undefined_default=True
-        ),
-    }
-
-
-def is_forum_daily_digest_enabled():
-    """Returns whether forum notification features should be visible"""
-    return waffle_flags()[ENABLE_FORUM_DAILY_DIGEST].is_enabled()

lms/djangoapps/discussion/views.py

@@ -30,7 +30,7 @@ import openedx.core.djangoapps.django_comment_common.comment_client as cc
 from lms.djangoapps.courseware.access import has_access
 from lms.djangoapps.courseware.courses import get_course_with_access
 from lms.djangoapps.courseware.views.views import CourseTabView
-from lms.djangoapps.discussion.config.waffle import is_forum_daily_digest_enabled
+from lms.djangoapps.discussion.config.settings import is_forum_daily_digest_enabled
 from lms.djangoapps.discussion.django_comment_client.base.views import track_thread_viewed_event
 from lms.djangoapps.discussion.django_comment_client.constants import TYPE_ENTRY
 from lms.djangoapps.discussion.django_comment_client.permissions import has_permission

lms/urls.py

@@ -26,6 +26,7 @@ from lms.djangoapps.courseware.views import views as courseware_views
 from lms.djangoapps.courseware.views.index import CoursewareIndex
 from lms.djangoapps.courseware.views.views import CourseTabView, EnrollStaffView, StaticCourseTabView
 from lms.djangoapps.discussion import views as discussion_views
+from lms.djangoapps.discussion.config.settings import is_forum_daily_digest_enabled
 from lms.djangoapps.discussion.notification_prefs import views as notification_prefs_views
 from lms.djangoapps.instructor.views import instructor_dashboard as instructor_dashboard_views
 from lms.djangoapps.instructor_task import views as instructor_task_views
@@ -701,7 +702,7 @@ if settings.FEATURES.get('ENABLE_DISCUSSION_SERVICE'):
         ),
     ]
 
-if settings.FEATURES.get('ENABLE_FORUM_DAILY_DIGEST'):
+if is_forum_daily_digest_enabled():
     urlpatterns += notification_prefs_urls
 
 urlpatterns += [