Add GitHub logo button and icon to DemoMainLayout

[AClerbois]

Pull Request

📖 Description

Add an anchor to point to Github repo with the branch v5

🎫 Issues

N/A

👩‍💻 Reviewer Notes

Open the example demo page and check if the logo is available and if you click on it you can reach the dev-v5 branch on the Github FluentUIBlazor repo

✅ Checklist

General

• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.

Component-specific

• I have added a new component
• I have added Unit Tests for my new component
• I have modified an existing component
• I have validated the Unit Tests for an existing component
• I have updated the Example demo doc

⏭ Next Steps

When you will merge the branch v5 to the new version, you should replace the target link

[Copilot]

Pull request overview

This PR adds a GitHub logo button to the DemoMainLayout header that links to the dev-v5 branch of the FluentUI Blazor repository. The implementation creates a custom GitHubIcon class and uses JavaScript interop to open the link in a new tab.

• Added a custom GitHubIcon class with the GitHub logo SVG path
• Implemented a button in the header with click handler to open the GitHub repository
• Added OpenUrlInNewTabAsync method to handle external link navigation

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
examples/Demo/FluentUI.Demo.Client/Layout/GitHubIcon.cs	New custom icon class containing the GitHub logo SVG path
examples/Demo/FluentUI.Demo.Client/Layout/DemoMainLayout.razor.cs	Added helper method to open URLs in new tabs via JavaScript interop
examples/Demo/FluentUI.Demo.Client/Layout/DemoMainLayout.razor	Added GitHub button to the header with icon and external link functionality

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[AClerbois]

@dvoituron & @vnbaaij If it is ok, we can merge to dev-v5 :-)

[dvoituron]

@dvoituron & @vnbaaij If it is ok, we can merge to dev-v5 :-)

The icon class could be include in the razor code behind (a sub class). To avoid to create a file only for that.