System.NullReferenceException Xamarin forms Tizen

## 🐛 Bug Report

On Xamarin Forms Tizen

System.NullReferenceException: Object reference not set to an instance of an object.
at MediaManager.Forms.Platforms.Tizen.VideoViewRenderer.OnElementChanged(ElementChangedEventArgs`1 args)

### Expected behavior

### Reproduction steps

### Configuration

Xamarin Forms 4.7.0

**Version:** 0.9.7

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


Start at MediaManager.Forms.Platforms.Tizen.VideoViewRenderer.OnElementChanged, the stack-trace entry named in the report. Reproduce the NullReferenceException with Xamarin Forms 4.7.0 and version 0.9.7 on Tizen, then identify which object is null and verify that the exception no longer occurs.

Written by the indexing model from the issue text.