MvxMasterDetailPage doesn't work on UWP
## 🐛 Bug Report

After migrated to Mvx 8.0.2 from Mvx 7.1.2, MvxMasterDetailPage doesn't work properly on UWP, in fact, master page (menu) is blank. No issue on IOS and Android 

### Expected behavior
Master Page should be visible.

### Reproduction steps
Create a new project with MvxMasterDetailPage with some element in menu page.

### Configuration
No particular configuration is needed

**Version:** 8.0.2

**Platform:** 
- [ ] :iphone: iOS
- [ ] :robot: Android
- [ ] :checkered_flag: WPF
- [X] :earth_americas: UWP
- [ ] :apple: MacOS
- [ ] :tv: tvOS
- [ ] :monkey: Xamarin.Forms
