feat: added sort by recent activity for activity stats api (#31252)

Co-authored-by: adeel.tajamul <adeel.tajamul@arbisoft.com>

lms/djangoapps/discussion/rest_api/api.py

@@ -1700,7 +1700,7 @@ def get_course_discussion_user_stats(
         order_by = order_by or UserOrdering.BY_FLAGS
     else:
         order_by = order_by or UserOrdering.BY_ACTIVITY
-        if order_by != UserOrdering.BY_ACTIVITY:
+        if order_by == UserOrdering.BY_FLAGS:
             raise ValidationError({"order_by": "Invalid value"})
 
     if not ENABLE_LEARNERS_STATS.is_enabled(course_key):

lms/djangoapps/discussion/rest_api/forms.py

@@ -24,6 +24,7 @@ from openedx.core.djangoapps.util.forms import ExtendedNullBooleanField, MultiVa
 class UserOrdering(TextChoices):
     BY_ACTIVITY = 'activity'
     BY_FLAGS = 'flagged'
+    BY_RECENT_ACTIVITY = 'recency'
 
 
 class _PaginationForm(Form):

lms/djangoapps/discussion/rest_api/tests/test_views.py

@@ -3115,9 +3115,11 @@ class CourseActivityStatsTest(ForumsEnableMixin, UrlResetMixin, CommentsServiceM
     @ddt.data(
         ("moderator", "flagged", "flagged"),
         ("moderator", "activity", "activity"),
+        ("moderator", "recency", "recency"),
         ("moderator", None, "flagged"),
         ("user", None, "activity"),
         ("user", "activity", "activity"),
+        ("user", "recency", "recency"),
     )
     @ddt.unpack
     @mock.patch.dict("django.conf.settings.FEATURES", {"ENABLE_DISCUSSION_SERVICE": True})