Animation not work on iOS after package update to version 4.x

## 🐛 Bug Report

In my Xamarin.Forms project I use v3.1.3 of this package and all works fine on android and iOS, I tryied to update package to version 4.0.11, but in iOS animations stopped to work while in android still work fine.

### Expected behavior
Animation still work on iOS after update package

### Reproduction steps
1. Update nuget package from verion 3.1.3 to version 4.0.x
2. Remove AnimationViewRenderer.Init(); from AppDelegate in iOS project (as no longer mentioned in the readme)
3. Edit xaml old animation options (from Loop="True" to RepeatMode="Restart" and from IsPlaying="{Binding IsPlaying}" to IsAnimating="{Binding IsPlaying}")

### Configuration

**Version:** 3.1.3 -> **Version:** 4.0.x

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

Start with the iOS AppDelegate and the XAML animation configuration described in the reproduction steps, comparing package 3.1.3 with 4.0.x behavior. Reproduce the upgrade on Xamarin.Forms and verify that the same animation starts and repeats on iOS after the migration changes.

Written by the indexing model from the issue text.