Play video MediaPlayback in Ipad is not showing video, only audio can be heard

#493 System info

Issue occurs on: iOS
Plugin version: ^0.3.11
Flutter doctor output:

```
[✓] Flutter (Channel stable, v1.17.5, on Mac OS X 10.15.6 19G73, locale en-ID)

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 11.6)
[!] Android Studio (version 4.0)
✗ Flutter plugin not installed; this adds Flutter specific functionality.
✗ Dart plugin not installed; this adds Dart specific functionality.
[✓] VS Code (version 1.47.1)
[✓] Connected device (2 available)

! Doctor found issues in 1 category.
```

## Steps to Reproduce

When I try with url https://bcovlive-a.akamaihd.net/4feb3ffbde6146549f02fc9d3822a3cb/ap-southeast-1/6107106512001/playlist.m3u8
the video is not appear, just audio can be heard

1.

## Logs

```
Runner[52659:507420] [assertion] Error acquiring assertion: {
userInfo = {
RBSAssertionAttribute = ;
}
}
```

flutter analyze no issue:
```
No issues found!
```

Here flutter doctor -v
```
[✓] Flutter (Channel stable, v1.17.5, on Mac OS X 10.15.6 19G73, locale en-ID)
• Flutter version 1.17.5 at /Users/ilhamamirullah/flutter
• Framework revision 8af6b2f038 (3 weeks ago), 2020-06-30 12:53:55 -0700
• Engine revision ee76268252
• Dart version 2.8.4

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0)
• Android SDK at /Users/ilhamamirullah/Library/Android/sdk
• Platform android-30, build-tools 30.0.0
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
• All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.6)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 11.6, Build version 11E708
• CocoaPods version 1.9.3

[!] Android Studio (version 4.0)
• Android Studio at /Applications/Android Studio.app/Contents
✗ Flutter plugin not installed; this adds Flutter specific functionality.
✗ Dart plugin not installed; this adds Dart specific functionality.
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] VS Code (version 1.47.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.12.2

[✓] Connected device (2 available)
• iPhone SE (2nd generation) • ED05FA2D-572E-43E0-BF4B-0251F93EC18B • ios • com.apple.CoreSimulator.SimRuntime.iOS-13-6
(simulator)
• iPad Pro (12.9-inch) (4th generation) • 35401DB7-8968-4163-BA66-983BB5FCCA3F • ios • com.apple.CoreSimulator.SimRuntime.iOS-13-6
(simulator)

! Doctor found issues in 1 category.
```

Reproduce the report on the listed iPad/iOS 13.6 environment using the provided HLS URL and the plugin version ^0.3.11. Start by tracing the plugin's iOS WebView/media playback entry point; done means the video renders while its audio remains audible, with the reported MediaPlayback log understood or resolved.

Written by the indexing model from the issue text.