[experiments][serializers] Set beat_core_class correctly

beat/web/experiments/serializers.py

@@ -59,7 +59,7 @@ class ExperimentCreationSerializer(serializers.ModelSerializer):
 
     class Meta:
         model = Experiment
-        beat_core_class = beat.core.experiment
+        beat_core_class = beat.core.experiment.Experiment
         fields = [
             "name",
             "short_description",