In UWP the aspect ratio of the video is not correctly adjusted (Xamarin.Forms)

## 🐛 Bug Report
When I add the video player with a custom width and height on a page the video aspect ratio does not fit correctly to the indicated size causing the video controls to hide, this only happens in UWP.

### Expected behavior
In case of using a custom width and height, the video player in UWP must correctly adjust the aspect ratio of the video without losing the video controls.

### Reproduction steps
I have uploaded a repository where you can see the problem: https://github.com/nacompllo/MediaManagerUWPIssue

**In UWP the aspect ratio of the video is not correctly adjusted to the indicated size and the video controls are lost.**


### Configuration
Plugin.MediaManager.Forms 1.0.9
Xamarin.Forms 5.0.0.2083

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

Start with the linked MediaManagerUWPIssue reproduction repository and the UWP video-player implementation in XamarinMediaManager. Reproduce the custom-width and custom-height case on UWP, then trace how sizing affects the aspect ratio and video controls. Done means the video fits the indicated dimensions without hiding its controls.

Written by the indexing model from the issue text.