🐛(api/client) fix has_listed_course_runs course filter

The filter `has_listed_course_runs` return non distinct course. So when
filtering course whose have listed course runs it returns the resource as many
as it has listed course runs.

src/backend/joanie/core/filters/client.py

@@ -67,6 +67,8 @@ def filter_has_listed_course_runs(self, queryset, _name, value):
         Filter resource by looking for course runs which are listed.
         """
         if value is True:
-            return queryset.filter(course_runs__is_listed=True)
+            filtered_queryset = queryset.filter(course_runs__is_listed=True)
+        else:
+            filtered_queryset = queryset.exclude(course_runs__is_listed=True)
 
-        return queryset.exclude(course_runs__is_listed=True)
+        return filtered_queryset.distinct()

src/backend/joanie/tests/core/test_api_course.py

@@ -133,6 +133,8 @@ def test_api_course_list_filter_has_listed_course_runs(self):
         courses = factories.CourseFactory.create_batch(3)
         factories.CourseRunFactory(course=courses[0], is_listed=False)
         factories.CourseRunFactory(course=courses[0], is_listed=True)
+        factories.CourseRunFactory(course=courses[0], is_listed=True)
+        factories.CourseRunFactory(course=courses[1], is_listed=False)
         factories.CourseRunFactory(course=courses[1], is_listed=False)
 
         # Give user access to all courses