Python: Add chat completion agent code interpreter sample

[TaoChenOSU]

Motivation and Context

Closing #10962

Description

1. Add a sample to demonstrate how to create a chat completion agent with code interpreter capabilities using the Azure Container Apps session pool service.
2. Fix a bug that cause the session tool to throw because the upload API doesn't return the file uploaded.
3. Modify unit tests accordingly.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
core_plugins/sessions_python_tool
sessions_python_plugin.py	134	8	94%	69, 82, 84–85, 87, 89, 91, 99
TOTAL	27106	4619	82%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3624	22 💤	0 ❌	0 🔥	2m 2s ⏱️