fix: allow timeslot to be null in the playout serializer

program/serializers.py

@@ -1313,7 +1313,7 @@ class PlayoutProgramEntrySerializer(BasicProgramEntrySerializer):
             model = Note
             fields = ["id", "title"]
 
-    timeslot = TimeSlotSerializer()
+    timeslot = TimeSlotSerializer(allow_null=True)
     show = PlayoutShowSerializer()
     episode = PlayoutEpisodeSerializer(allow_null=True, source="timeslot.note")
     schedule = PlayoutScheduleSerializer(allow_null=True, source="timeslot.schedule")