iOS can't dismiss Modal!

Description

On iOS the <Modal> component cannot be dismissed by dragging down. (gesture is a native behaviour on iOS)

The reason for that being is that the onDismiss or onRequestClose function is never called. It is only being called on tvOS.

React Native version:

info Fetching system and libraries information...
(node:10129) Warning: Accessing non-existent property 'padLevels' of module exports inside circular dependency
(Use `node --trace-warnings ...` to show where the warning was created)
System:
    OS: macOS 10.15.5
    CPU: (16) x64 Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz
    Memory: 2.78 GB / 32.00 GB
    Shell: 5.7.1 - /bin/zsh
  Binaries:
    Node: 14.4.0 - /usr/local/bin/node
    Yarn: 1.22.4 - /usr/local/bin/yarn
    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 13.5, DriverKit 19.0, macOS 10.15, tvOS 13.4, watchOS 6.2
    Android SDK:
      API Levels: 25, 28, 29
      Build Tools: 28.0.3, 29.0.2, 29.0.3, 30.0.0, 30.0.0, 30.0.0
      System Images: android-29 | Google APIs Intel x86 Atom, android-29 | Google Play Intel x86 Atom
      Android NDK: 21.2.6472646
  IDEs:
    Android Studio: 4.0 AI-193.6911.18.40.6514223
    Xcode: 11.5/11E608c - /usr/bin/xcodebuild
  Languages:
    Java: 1.8.0_252 - /usr/bin/javac
    Python: 2.7.16 - /usr/bin/python
  npmPackages:
    @react-native-community/cli: Not Found
    react: 16.13.1 => 16.13.1 
    react-native: 0.63.0 => 0.63.0 
  npmGlobalPackages:
    *react-native*: Not Found

Steps To Reproduce

1. Create <Modal> component and set visible and onRequestClose properties
2. Open Modal by setting visible to true
3. Try to close Modal by dragging down

Expected Results

Modal should be dragged down and onDismiss or onRequestClose should be called

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

<Modal
  presentationStyle="pageSheet"
  visible={true}
  onRequestClose={() => console.log("will never be called.")} />

从 React Native Modal 组件的 iOS 行为入手，使用提供的示例复现 presentationStyle="pageSheet" 的情况。追踪为什么向下拖动不会调用 onDismiss 或 onRequestClose，然后在 iOS 上验证关闭操作会调用预期的 callback。