Update docfx.json

[raprice]

What changes to the docs does this PR provide?

This PR changes the uhfHeaderId value to MSDocsWindows. In order to meet platform architectural requirements, this content must use the Windows header. This PR makes that change.

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] Correctly picked the right branch to base the change off (dev for new features, main for typos/improvements)
• [ ] For new pages, used the provided template
• [ ] For new features, added an entry in the Table of Contents
• [x] Ran against a spell and grammar checker
• [x] Contains NO breaking changes

Other information

[learn-build-service-prod[bot]]

Learn Build status updates of commit 5c1fb02:

:warning: Validation status: warnings

File	Status	Preview URL	Details
docs/docfx.json	:warning:Warning		Details

docs/docfx.json

• Line 36, Column 50: [Warning: ms-prod-technology-invalid - See documentation] Invalid value for 'ms.technology': 'windows-community-toolkit' is not valid with 'ms.prod' value 'dotnet-communitytoolkit'.

For more details, please refer to the build report.

Note: Your PR may contain errors or warnings or suggestions unrelated to the files you changed. This happens when external dependencies like GitHub alias, Microsoft alias, cross repo links are updated. Please use these instructions to resolve them.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel