Media Player Speed is not working in IOS

## 🐛 Bug Report

Media Player speed property is not working for IOS, but same is working fine in Android.

### Expected behavior

When set Speed to 2.0 then audio or video need to play faster than the normal speed.

### Reproduction steps

CrossMediaManager.Current.Speed = 2F;
await CrossMediaManager.Current.Play("https://ia800806.us.archive.org/15/items/Mp3Playlist_555/AaronNeville-CrazyLove.mp3");

Still audio is playing in normal speed. but same code works in android.

### Configuration

**Version:** 1.0.8

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

Start by reproducing the issue on iOS with CrossMediaManager.Current.Speed = 2F followed by the provided audio URL, then compare the result with Android. Done means audio or video plays at twice normal speed on iOS when Speed is set to 2.0.

Written by the indexing model from the issue text.