Repository: flutter
Issue: iOS Splashscreen/Launchscreen with Navigationbar jumps under status bar and turns black before finishing
Labels: platform-ios,framework,engine,has reproducible steps,P2,found in release: 3.3,found in release: 3.6,team-ios,triaged-ios

## Steps to Reproduce

<!-- You must include full steps to reproduce so that we can reproduce the problem. -->

1. Run `flutter create fluttersplashtest`.
2. Put this (https://pastebin.com/cMqy1w8N) LaunchScreen.storyboard in ios/Runner/Base.lproj
3. Run `flutter run`

**Expected results:** <!-- what did you want to see? -->
The launchscreen should remain static until the app is loaded and simply disappear once that is the case.
Video - In a regular iOS app (without flutter) this works: https://i.imgur.com/aoPGKEN.mp4

**Actual results:** <!-- what did you see? -->
The launchscreen changes position and turns partially black shortly before the app is loaded.
Video - https://i.imgur.com/Earh1GA.mp4

It's quite important that this works, as Apples Human Interface Guidelines (https://developer.apple.com/design/human-interface-guidelines/ios/visual-design/launch-screen/) want you to create a splashscreen that looks like the first page of your app.

<details>
  <summary>Logs</summary>

<!--
      Run your application with `flutter run --verbose` and attach all the
      log output below between the lines with the backticks. If there is an
      exception, please see if the error message includes enough information
      to explain how to solve the issue.
-->
```
flutter run --verbose
https://pastebin.com/W6M3YAhu
```
<!--
     Run `flutter analyze` and attach any output of that command below.
     If there are any analysis errors, try resolving them before filing this issue.
-->
```
flutter analyze
Analyzing fluttersplashtest...                                          
No issues found! (ran in 4.4s)
```
<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
flutter doctor -v
[✓] Flutter (Channel stable, 1.22.2, on Mac OS X 10.15.6 19G71a, locale en-GB)
    • Flutter version 1.22.2 at /Users/auligpromotions/Documents/Flutter/flutter
    • Framework revision 84f3d28555 (3 weeks ago), 2020-10-15 16:26:19 -0700
    • Engine revision b8752bbfff
    • Dart version 2.10.2

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
    • Android SDK at /Users/auligpromotions/Library/Android/sdk
    • Platform android-30, build-tools 30.0.2
    • 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 12.0.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.0.1, Build version 12A7300
    • CocoaPods version 1.9.3

[✓] Android Studio (version 4.0)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 50.0.1
    • Dart plugin version 193.7547
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6222593)

[✓] Connected device (1 available)
    • iPhone SE (2nd generation) (mobile) • 3EA3BB56-DA5F-4A00-BDD6-436082E84945
      • ios • com.apple.CoreSimulator.SimRuntime.iOS-14-0 (simulator)

• No issues found!
```

</details>