Python: Add UserSecurityContext to SK python

[slreznit]

Motivation and Context

Expose UserSecurityContext in SK python via ExtraBody as this is available in Azure only. https://learn.microsoft.com/en-us/dotnet/api/azure.ai.openai.usersecuritycontext

Description

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 :smile:

[markwallace-microsoft]

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3439	5 :zzz:	0 :x:	0 :fire:	1m 44s :stopwatch:

[moonbox3]

@slreznit closing this PR as there hasn't been any activity since the end of April. If you'd like to move forward, please re-open or create a new PR. Thanks.