Fix workflow samples

python/samples/03-workflows/composition/sub_workflow_kwargs.py

@@ -34,7 +34,7 @@ Key Concepts:
 
 Prerequisites:
 - FOUNDRY_PROJECT_ENDPOINT must be your Azure AI Foundry Agent Service (V2) project endpoint.
-- Environment variables configured
+- FOUNDRY_MODEL must be set to your Azure OpenAI model deployment name.
 """
 
 
@@ -84,7 +84,7 @@ async def main() -> None:
     # Create chat client
     client = FoundryChatClient(
         project_endpoint=os.environ["FOUNDRY_PROJECT_ENDPOINT"],
-        model=os.environ["AZURE_AI_MODEL_DEPLOYMENT_NAME"],
+        model=os.environ["FOUNDRY_MODEL"],
         credential=AzureCliCredential(),
     )