[iOS] Animation stops when you re-open the app from background

## 🐛 Bug Report

I have a CollectionView with several animations. When I put the app in the background and open it again, the animations stop. This only affects iOS, it works on Android.

This also happens when using a ListView.

### Expected behavior

Animations should continue to run after reopening the app from the background.

### Reproduction steps

Branch with sample code: https://github.com/areimche/LottieXamarin/tree/test_background_bug

- start the example app
- click on "List Example"
- scroll to bottom
- scroll to top
- leave the app
- reopen the app from background

### Configuration

**Version:** 4.0.9

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

Start with the reproduction branch test_background_bug and run the example app through the listed List Example steps, including both ListView and CollectionView behavior. Trace the iOS path involved when the app is reopened from the background. Done means animations continue running after reopening on iOS while Android behavior remains intact.

Written by the indexing model from the issue text.