KeyboardAvoidingView mistakingly adds white space on screen bottom after being untangled

[Description]

I wrapped a view as a footer inside KeyboardAvoidingView. It works properly before the keyboard has been untoggled. However, after the keyboard is untoggled, it adds a white space on the bottom of the screen. The height of the white space is as big as the keyboardVerticalOffset. This white space shouldn't exist.

React Native version:

System:
OS: macOS 10.15.6
CPU: (8) x64 Intel(R) Core(TM) i7-7920HQ CPU @ 3.10GHz
Memory: 28.43 MB / 16.00 GB
Shell: 3.2.57 - /bin/bash
Binaries:
Node: 12.18.1 - /usr/local/bin/node
Yarn: Not Found
npm: 6.14.5 - /usr/local/bin/npm
Watchman: 4.9.0 - /usr/local/bin/watchman
Managers:
CocoaPods: 1.9.3 - /usr/local/bin/pod
SDKs:
iOS SDK:
Platforms: iOS 13.6, DriverKit 19.0, macOS 10.15, tvOS 13.4, watchOS 6.2
Android SDK: Not Found
IDEs:
Android Studio: Not Found
Xcode: 11.6/11E708 - /usr/bin/xcodebuild
Languages:
Java: 14.0.1 - /usr/bin/javac
Python: 2.7.16 - /usr/bin/python
npmPackages:
@react-native-community/cli: Not Found
react: ~16.11.0 => 16.11.0
react-native: https://github.com/expo/react-native/archive/sdk-38.0.1.tar.gz => 0.62.2
npmGlobalPackages:
react-native: Not Found

Steps To Reproduce

Provide a detailed list of steps that reproduce the issue.

1. Use KeyboardAvoidingView, set keyboardVerticalOffset to any value
2. Put a view inside KeyboardAvoidingView, set the position as absolute, and set the bottom to 0

Expected Results

The white space for keyboardVerticalOffset should only exist when the keyboard is toggled.

Snack, code example, screenshot, or link to a repository:

<KeyboardAvoidingView
      behavior={Platform.OS == "ios" ? "padding" : "height"}
      keyboardVerticalOffset={48}
      style={{width: "100%",
                   height: "100%",
                   position: "absolute",
                   zIndex: 1,}}
>
      <View
              style={{width: "100%",
                            position: "absolute",
                            height: 56,
                            bottom: 0,}}
      >
              <SubmitButton/>
       </View>
</KeyboardAvoidingView>

Bắt đầu bằng cách tái hiện ví dụ KeyboardAvoidingView được cung cấp trên iOS, với behavior được đặt thành padding hoặc height và keyboardVerticalOffset được đặt thành 48. Kiểm tra implementation của KeyboardAvoidingView và xác minh rằng khoảng trống bên dưới chỉ xuất hiện khi bàn phím đang hiển thị, sau đó xác nhận rằng footer được cung cấp với vị trí tuyệt đối hoạt động đúng sau khi bàn phím được ẩn.