Python: added code sample to download file from code interpreter

[beyondszine]

Motivation and Context

Just adding more sample to help user understand how to retrieve file from code interpreter tool. The file is generated in open ai container that runs the code. This code shows a way to retrieve that generated file.
Ex: a graph generated from matplotlib

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? If yes, add "[BREAKING]" prefix to the title of the PR.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a new Python sample demonstrating how to upload a CSV to Code Interpreter, generate charts, and download generated files from the container citations to local disk.

Changes:

• Added a shared CSV dataset for chart generation (city populations).
• Added a new OpenAI provider sample showing upload → run → extract citations → download outputs → cleanup.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
python/samples/shared/sample_assets/sample_city_populations.csv	Adds a sample dataset used by the new Code Interpreter download sample.
python/samples/02-agents/providers/openai/client_with_code_interpreter_files_download.py	New end-to-end sample for downloading files generated inside the Code Interpreter container.