[MenuItem] trigger OnClick on FluentMenuItem when enter is pressed onkeydown

[adamint]

Pull Request

📖 Description

FluentMenuItem should treat a keyboard enter the same as OnClick, as they are effectively the same and fits inside our accessible by default tenet. Consumers of fluentui-blazor should not need to explicitly add support for this behavior themselves to be accessible.

🎫 Issues

context: dotnet/aspire#10139

👩‍💻 Reviewer Notes

📑 Test Plan

✅ 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

⏭ Next Steps