Python: Bug: Assistant Agent puts code interpreter streaming chunks to `on_intermediate_message`

[TaoChenOSU]

Describe the bug
The code interpreter puts code interpreter streaming chunks to the on_intermediate_message callback, which is supposed to accept fully formed messages.

To Reproduce

1. Create an Assistant Agent with code interpreter.
2. Invoke the agent in streaming mode with an on_intermediate_message callback.

The bug can be traced from the following lines:

1. https://github.com/microsoft/semantic-kernel/blob/main/python/semantic_kernel/agents/open_ai/openai_assistant_agent.py#L1046
2. https://github.com/microsoft/semantic-kernel/blob/main/python/semantic_kernel/agents/open_ai/assistant_thread_actions.py#L487 where the tool_content is a streaming chunk.

Expected behavior
The fully code snippet should be passed to the callback.

Platform

• Language: Python