Jonatan/mon 2665 fix data ingetion bug (#386)

Author: JKL98ISR

backend/deepchecks_monitoring/api/v1/model.py

@@ -368,6 +368,9 @@ def truncate_date(col, agg_time_unit: str = "day"):
 
     union_q = sa.union_all(*model_queries)
 
+    if not model_queries:
+        return {}
+
     rows = (await session.execute(
         sa.select(union_q.c.model_id, union_q.c.timestamp, union_q.c.count, union_q.c.label_count)
     )).fetchall()