.NET: Fix issue #2181 - Sample type mismatch

[Vaccarini-Lorenzo]

Motivation and Context

This change fixes the workflow break in 07_MixedWorkflowAgentsAndExecutors, where the edge from JailbreakDetector to JailbreakSync was consistently dropped due to a payload type mismatch.

The sample defines JailbreakSyncExecutor as Executor<ChatMessage>, but the agent host emits a collection of messages (List<ChatMessage>). Because the executor declared a narrower input type, edge delivery failed with delivery_status: dropped type mismatch, preventing all downstream components (JailbreakSync, ResponseAgent, FinalOutput) from running.

Updating the executor to accept List<ChatMessage> restores compatibility with the emitted payload, allowing the workflow to execute end-to-end as intended.

Fixes: #2181

Description

• Updated the JailbreakSyncExecutor constructor from:

  Executor<ChatMessage>("JailbreakSync")

  to:

  Executor<List<ChatMessage>>("JailbreakSync")

• Ensures that the executor’s declared input type matches the message collection emitted by the agent host.
• Restores proper delivery of the edge JailbreakDetector → JailbreakSync.
• Verified the fix by running the full sample:
  • StringToChat, JailbreakDetector, JailbreakSync, ResponseAgent, and FinalOutputExecutor all execute correctly.
  • Console output now includes the JailbreakSync formatted message and the final agent response.
• Confirmed via OpenTelemetry that:
  • edge_group.delivered = true for all affected edges.
  • No further type-mismatch drops occur.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change?

[Copilot]

Pull Request Overview

This PR fixes a type mismatch bug in sample 07_MixedWorkflowAgentsAndExecutors that prevented the workflow from executing end-to-end. The JailbreakSyncExecutor has been updated to accept List<ChatMessage> instead of a single ChatMessage, matching the message collection emitted by the agent host.

• Updated JailbreakSyncExecutor to inherit from Executor<List<ChatMessage>> instead of Executor<ChatMessage>
• Modified the executor's HandleAsync method to extract the last assistant message from the list and process it appropriately
• Added logic to handle the message collection with proper null-checking using LastOrDefault

[Vaccarini-Lorenzo]

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