Add behavior for Validation-Guide label / Bot Trigger Updates

[Trenly]

Checklist for Pull Requests

• Have you signed the Contributor License Agreement?

• Adds Validation-Guide label on common PR validation failures
• Adds a response when Validation-Guide is added
• Adds Zapret2 to flagged packages
• Clarifys existing flagged packages in comments
• Removes obsolete Manifest-Content-Incomplete trigger
• Updates License-Blocks-Install instructions
• Removes outdated and incorrect Validation-Smart-Screen trigger
• Removes outdated and incorrect Windows-Feature trigger
• Removes Validate-Domain-Installer on changes pushed to PR (it will be re-added on pipeline rerun if needed)

@denelon / @mdanish-kh

Microsoft Reviewers: Open in CodeFlow