[Azure AI Agents] Update links to point to correct repo.

[trangevi]

Description

Please add an informative description that covers that changes made by the pull request and link all relevant issues.

If an SDK is being regenerated based on a new swagger spec, a link to the pull request containing these swagger spec changes has been included above.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[Copilot]

Pull Request Overview

This PR updates documentation links and sample references to point to the correct Azure AI Agents repository and adjusts the CODEOWNERS file to include additional reviewers.

• Updated URL paths in README.md for function tool specifications, user function examples, asynchronous function samples, and next steps.
• Extended CODEOWNERS to include new code reviewers for the Azure AI Agents SDK.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
sdk/ai/azure-ai-agents/README.md	Updated sample and documentation links to reflect the correct repo
.github/CODEOWNERS	Added new owners to support the Azure AI Agents repository