small fix to simulate sample (#39331)

* small fix to simulate sample

* update changelog

Author: slister1001

sdk/evaluation/azure-ai-evaluation/CHANGELOG.md

@@ -14,6 +14,7 @@
 - Content safety evaluators (violence, self harm, sexual, hate/unfairness) return the maximum result as the
   main score when aggregating per-turn evaluations from a conversation into an overall
   evaluation score. Other conversation-capable evaluators still default to a mean for aggregation.
+- Fixed bug in non adversarial simulator sample where `tasks` undefined
 
 ### Other Changes
 - Changed minimum required python version to use this package from 3.8 to 3.9

sdk/evaluation/azure-ai-evaluation/samples/evaluation_samples_simulate.py

@@ -232,7 +232,7 @@ async def callback(
                 target=callback,
                 max_conversation_turns=2,
                 text="some text",
-                tasks=tasks,
+                tasks=["tasks"],
                 api_call_delay_sec=1,
                 num_queries=1,
             )