.Net: Update obsolete links

[sinwoobang]

Motivation and Context

1. This change is required to ensure all documentation links are up-to-date.
2. It solves the problem of users encountering broken or outdated links.
3. It contributes to the scenario of maintaining accurate and helpful documentation for users.
4. N/A

Description

Updated several obsolete links in the documentation to point to the current and correct URLs. This ensures users have access to the most recent and relevant information.

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 😄

[sinwoobang]

@microsoft-github-policy-service agree company="Global AI Platform Corporation"