android onScrollEndDrag throttled by scrollEventThrottle

Description

on android, onScrollEndDrag can be prevented by a non-zero scrollEventThrottle value.

Steps to reproduce

• using below code, scroll/fling with any kind of velocity and notice the onScrollEndDrag message is not logged.
• repeat without flinging/no velocity (hold same scroll position for >250ms before releasing), notice the onScrollEndDrag message is logged.

<FlatList
  data={[1,2,3,4]}
  onScrollEndDrag={() => console.log('onScrollEndDrag')}
  renderItem={() => <View style={{height: 400}} />}
  scrollEventThrottle={250}
/>

React Native Version

0.73.6

Affected Platforms

Runtime - Android

Output of npx react-native info

info Fetching system and libraries information...
System:
  OS: macOS 14.4.1
  CPU: (10) arm64 Apple M1 Pro
  Memory: 264.94 MB / 32.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 18.20.1
    path: ~/.nvm/versions/node/v18.20.1/bin/node
  Yarn:
    version: 1.22.19
    path: ~/.yarn/bin/yarn
  npm:
    version: 7.24.2
    path: ~/code/react-native-sydney-components/node_modules/.bin/npm
  Watchman:
    version: 2024.04.15.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.15.2
    path: /Users/AG63864/.rbenv/shims/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 23.4
      - iOS 17.4
      - macOS 14.4
      - tvOS 17.4
      - visionOS 1.1
      - watchOS 10.4
  Android SDK:
    API Levels:
      - "33"
      - "34"
    Build Tools:
      - 33.0.1
      - 34.0.0
    System Images:
      - android-34 | Google Play ARM 64 v8a
    Android NDK: Not Found
IDEs:
  Android Studio: 2023.2 AI-232.10300.40.2321.11567975
  Xcode:
    version: 15.3/15E204a
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.11
    path: /Users/AG63864/.jenv/shims/javac
  Ruby:
    version: 3.1.1
    path: /Users/AG63864/.rbenv/shims/ruby
npmPackages:
  "@react-native-community/cli": Not Found
  react:
    installed: 18.2.0
    wanted: 18.2.0
  react-native:
    installed: 0.73.6
    wanted: 0.73.6
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: false
  newArchEnabled: false
iOS:
  hermesEnabled: Not found
  newArchEnabled: Not found

info React Native v0.74.0 is now available (your project is running on v0.73.6).
info Changelog: https://github.com/facebook/react-native/releases/tag/v0.74.0
info Diff: https://react-native-community.github.io/upgrade-helper/?from=0.74.0
info For more info, check out "https://reactnative.dev/docs/upgrading?os=macos".

Stacktrace or Logs

n/a

Reproducer

https://github.com/scrungrth/android-scroll-throttle-reproducer

Screenshots and Videos

No response

Start by reproducing the issue with the linked Android scroll-throttle reproducer and the FlatList example, comparing fling and non-fling behavior. Trace React Native's Android handling of onScrollEndDrag alongside scrollEventThrottle, then add regression coverage for both cases. Done means the callback is delivered consistently when a non-zero throttle is configured.