fix: class missing in FluentMenu when anchored

[JamesNK]

🐛 Bug Report

I've added a class to a FluentMenu like this:

<FluentMenu @ref="_menu" Class="aspire-menu">
...

The class name is written to HTML when the fluent menu isn't anchored:

But when it is anchored I don't see the style written anywhere. It looks like should should go onto the div, here. But it's missing in output HTML.

💻 Repro or Code Sample

See above

🤔 Expected Behavior

Class should be written somewhere.

😯 Current Behavior

Not written anywhere.

💁 Possible Solution

🔦 Context

🌍 Your Environment

• OS & Device: [e.g. MacOS, iOS, Windows, Linux] on [iPhone 7, PC]
• Browser [e.g. Microsoft Edge, Google Chrome, Apple Safari, Mozilla FireFox]
• .NET and Fluent UI Blazor library Version [e.g. 8.0.2 and 4.4.1]

[Tyme-Bleyaert]

I have the same issue when the FluentMenu has the UseMenuService parameter enabled.
When looking at the source of FluentMenuProvider:
I would expect the menu service to use the menu's class and not the Class of the service provider instance.

Edit: the same for the style.