SIENTIAPDE-1712

Add unique constraint on (model_id, timestamp, variable) in schema and implement idempotent export test to ensure no duplicates are created. Update CoreScouter and related tests to handle conflict resolution by ignoring duplicates.

scouter/workflow/sub_workflows/core_scouter.py

@@ -118,6 +118,7 @@ class CoreScouter:
                 'schema': input_data['schema'],
                 'table_name': input_data['table_name'],
                 'data': held_data,
+                'on_conflict': 'ignore',
                 'timestamp_conversion': {'column': 'timestamp', 'format': DATETIME_FORMAT_WITH_TZ},
             },
             retry_policy=retry_policy,