[C#] port: TeamsAttachmentDownloader, vision support...etc

[singhk97]

Linked issues

closes: #1011 #1182 (issue number)

Details

Implements the TeamsAttachmentDownloader and OpenAI/AOAI Vision model support

Change details

• Bumped Azure.AI.OpenAI to version 1.0.0-beta.17
• Implemented TeamsAttachmentDownloader
• Auxilliary changes in the Application/ and AI/ code.
• Implemented and tested CardGazer sample.

Breaking Change

• ChatMessage.Content is changed from string? to object? since it can hold a string or IEnumerable<MessageContentParts>

Attestation Checklist

• [x] My code follows the style guidelines of this project

• I have checked for/fixed spelling, linting, and other errors

• I have commented my code for clarity

• I have made corresponding changes to the documentation (updating the doc strings in the code is sufficient)

• My changes generate no new warnings

• I have added tests that validates my changes, and provides sufficient test coverage. I have tested with:

  • Local testing
  • E2E testing in Teams

• New and existing unit tests pass locally with my changes