feat: Made UIElement Key Events public

[TranquilAbyss]

PR Details

Made KeyPress Events public on UI Elements to allow for custom UI Hotkeys

Related Issue

https://github.com/stride3d/stride/issues/2515

Types of changes

• [ ] Docs change / refactoring / dependency upgrade
• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist

This is my first PR, let me know if I am missing something. All the UI tests passed, I am still working on getting my environment setup for other tests.

• [ ] My change requires a change to the documentation.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.
• [x] I have built and run the editor to try this change out.

[TranquilAbyss]

@dotnet-policy-service agree