[Bug] [WPF] Some video links are missing audio, video or both

## 🐛 Bug Report

some high resolution videos play only audio with no video rendered or render nothing at all

### Expected behavior
playing a video link with sound plays normally
### Reproduction steps
1. add MediaManager forms nuget to the solution
2. call MediaManager.CrossMediaManager.Current.Init(); Forms.Init(); ... in MainWindow.xaml.cs
3. add videoView xaml with Source and AutoPlay=True or from code like this one:
http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_60fps_normal.mp4
4. depending on the video, sometimes it renders only audio sometimes nothing.

| Video link | resolution | Audio loaded? | Video rendered? | fps? |
|------------------------------------------------------------------------------------------------------|------------|--------------------|--------------------|------|
| [Link1](http://sample-videos.com/video123/mp4/240/big_buck_bunny_240p_30mb.mp4) | 360x240 | :heavy_check_mark: | :heavy_check_mark: | |
| [Link2](http://sample-videos.com/video123/mp4/720/big_buck_bunny_720p_10mb.mp4) | 1280x720 | :heavy_check_mark: | :heavy_check_mark: | |
| [Link3](http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_30fps_normal.mp4) | 1920x1080 | :white_check_mark: | :heavy_check_mark: | 30 |
| [Link4](http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_60fps_normal.mp4) | 1920x1080 | :white_check_mark: | :heavy_check_mark: | 60 |
| [Link5](http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_2160p_30fps_normal.mp4) | 3860x2160 | :white_check_mark: | :white_check_mark: | 30 |
| [Link6](http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_2160p_60fps_normal.mp4) | 3860x2160 | :white_check_mark: | :white_check_mark: | 60 |
| [Link7](http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_native_60fps_normal.mp4) | 4096x2250 | :white_check_mark: | :white_check_mark: | 60 |

### Configuration
* Visual Studio 2019 **16.2.4**
* Xamarin.Forms **4.2.0.709249**
* Xamarin.Forms.Platform.WPF **4.2.0.709249**
* Plugin.MediaManager.Forms **0.8.8**

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

**Note**: video links are all http because I encountered a problem if the link is https see this https://github.com/martijn00/XamarinMediaManager/issues/609

Reproduce the WPF issue using the listed high-resolution HTTP video links after the MediaManager.Forms initialization and VideoView setup described in the report. Compare audio and video behavior across the links; done means the affected videos consistently render both audio and video.

Written by the indexing model from the issue text.