[BUG] Chat with image example show error image_url should be object but receive string

[bobogogo1990]

Describe the bug
OpenAI API hits BadRequestError: Error code: 400 - {'error': {'message': "Invalid type for 'messages[1].content[0].image_url': expected an object, but got a string instead.", 'type': 'invalid_request_error', 'param': 'messages[1].content[0].image_url', 'code': 'invalid_type'}}

How To Reproduce the bug
Steps to reproduce the behavior, how frequent can you experience the bug:

1. use the lastest promptflow promptflow-tools to run chat-with-image
2. windows 12, python 3.10.16, promptflow-tools 1.4.0 promptflow 1.17.2

Expected behavior
answer "How many colors can you see?"

Screenshots

Running Information(please complete the following information):

• Promptflow Package Version using pf -v:

• Operating System: [e.g. Ubuntu 20.04, Windows 11] windows 12
• Python Version using python --version: 3.10.16

Additional context
Add any other context about the problem here.