feat!: General cleanup of legacy Studio page waffle flags and related code.

Remove the waffle flags and helper functions for all legacy Studio pages
that have been replaced by the Authoring MFE:
- legacy_studio.schedule_details
- legacy_studio.advanced_settings
- legacy_studio.grading
- legacy_studio.import
- legacy_studio.export
- legacy_studio.course_team
- legacy_studio.certificates
- legacy_studio.configurations

Also removes the course_waffle_flags REST API endpoint
(GET /api/contentstore/v1/course_waffle_flags) and its serializer, view,
and tests, as these only existed to expose the now-removed flags.

Simplifies URL helpers in utils.py to unconditionally return MFE URLs.

This work is part of #36108

BREAKING CHANGE: All of the above waffle flags are removed. The
GET /api/contentstore/v1/course_waffle_flags endpoint is removed.

Author: irfanuddinahmad

cms/djangoapps/contentstore/rest_api/v1/serializers/__init__.py

@@ -6,7 +6,6 @@
 from .course_index import CourseIndexSerializer  # noqa: F401
 from .course_rerun import CourseRerunSerializer  # noqa: F401
 from .course_team import CourseTeamSerializer  # noqa: F401
-from .course_waffle_flags import CourseWaffleFlagsSerializer  # noqa: F401
 from .grading import CourseGradingModelSerializer, CourseGradingSerializer  # noqa: F401
 from .group_configurations import CourseGroupConfigurationsSerializer  # noqa: F401
 from .home import CourseHomeTabSerializer, LibraryTabSerializer, StudioHomeSerializer  # noqa: F401

cms/djangoapps/contentstore/rest_api/v1/serializers/course_waffle_flags.py

@@ -18,7 +18,6 @@
     CourseTeamView,
     CourseTextbooksView,
     CourseVideosView,
-    CourseWaffleFlagsView,
     HelpUrlsView,
     HomePageCoursesView,
     HomePageLibrariesView,
@@ -139,11 +138,6 @@
         ContainerChildrenView.as_view(),
         name="container_children"
     ),
-    re_path(
-        fr'^course_waffle_flags(?:/{COURSE_ID_PATTERN})?$',
-        CourseWaffleFlagsView.as_view(),
-        name="course_waffle_flags"
-    ),
 
     # Authoring API
     # Do not use under v1 yet (Nov. 23). The Authoring API is still experimental and the v0 versions should be used

cms/djangoapps/contentstore/rest_api/v1/urls.py

@@ -6,7 +6,6 @@
 from .course_index import ContainerChildrenView, CourseIndexView  # noqa: F401
 from .course_rerun import CourseRerunView  # noqa: F401
 from .course_team import CourseTeamView  # noqa: F401
-from .course_waffle_flags import CourseWaffleFlagsView  # noqa: F401
 from .grading import CourseGradingView  # noqa: F401
 from .group_configurations import CourseGroupConfigurationsView  # noqa: F401
 from .help_urls import HelpUrlsView  # noqa: F401