Feature request: Expand the `MenuFlyout` example in `reactor-gallery`

Suggestion

The current MenuFlyout page in the Rust reactor-gallery sample only demonstrates two basic usage scenarios: a MenuFlyout with standard menu items, and a MenuFlyout with standard menu items and a separator.

It would be useful to expand this page into a more complete MenuFlyout showcase, similar to the MenuFlyout page in the WinUI 3 Gallery.

The goal is to demonstrate the different MenuFlyout capabilities and usage patterns that are available in WinUI 3, rather than only showing the most basic cases.

Specifically, I would like the reactor-gallery MenuFlyout page to include examples for:

• A MenuFlyout with ToggleMenuFlyoutItems and MenuFlyoutSeparator.
• A MenuFlyout with cascading menus.
• A MenuFlyout with SplitMenuFlyoutItems.
• A MenuFlyout with icons.
• A MenuFlyout with icons and Keyboard Accelerators.
• A MenuFlyout with RadioMenuFlyoutItems.

Ideally, the Rust reactor-gallery page would provide a similar set of interactive examples and overall presentation to the corresponding MenuFlyout page in the WinUI 3 Gallery.

I will attach a video to this issue showing the MenuFlyout page in the WinUI 3 Gallery as a visual reference for the desired result.

This would make the reactor-gallery example much more useful as a reference for Rust developers learning how to use MenuFlyout and its different item types with windows-reactor.

Thank you!

https://github.com/user-attachments/assets/f2b2d851-0c67-4fcd-ac16-0b8621ba2c2f