[Reactive] Forward the INotifyPropertyChange raised by VM to the BindableVM

[dr1rrb]

What would you like to be added:

Forward the INotifyPropertyChanges raised by VM to the BindableVM

Why is this needed:

BindableVM re-expose public properties from the VM, if VM raise INPC the view won't be udpated.

For which Platform:

• [x] iOS
• [x] Android
• [x] WebAssembly
• [x] WebAssembly renders for Xamarin.Forms
• [x] Windows
• [x] Build tasks

[ThaddeusChristopher]

This is the most important change that would make uno.extensions a viable choice in my current project.

Curious, could this enhancement also enable views to update from CommunityToolkit.Mvvm's source-generated bindings? Ex: On an ObservableObject when using the attributes [ObservableProperty] and [AlsoNotifyChangeFor].

I noticed these highly-desirable CommunityToolkit.Mvvm features appear to not update views when mixed with uno.extensions and Reactive. Likely because they have separate code-generated files (unless maybe it's just this ticket's bug?). Which is unfortunate, because anything dependency-injected by Uno.Extensions.Navigation sets the VM to Reactive, thus subverting CommunityToolkit.Mvvm and its handy attributes.

Of course, if Reactive could implement similar Attributes that would be just as useful!