feat: add coalasce over avg to stop returnin null values

insights/sources/rooms/query_builder.py

@@ -49,6 +49,6 @@ def sum(self, field_name: str):
     def avg(self, field_name: str):
         if not self.is_valid:
             self.build_query()
-        query = f"SELECT AVG(mr.{field_name}) AS value FROM public.rooms_room as r INNER JOIN public.dashboard_roommetrics AS mr ON mr.room_id=r.uuid {self.join_clause} WHERE {self.where_clause};"
+        query = f"SELECT COALESCE(AVG(mr.{field_name}), 0) AS value FROM public.rooms_room as r INNER JOIN public.dashboard_roommetrics AS mr ON mr.room_id=r.uuid {self.join_clause} WHERE {self.where_clause};"
 
         return query, self.params