Fetch API does not support getReader (response.body is undefined)

Description

When trying to read the response from Fetch as a stream, via getReader(), I get an error saying that resp.body is undefined. Logging the value of resp shows this:

{"_bodyBlob": {"_data": {"__collector": [Object], "blobId": "xxx", "name": "chat.txt", "offset": 0, "size": 42, "type": "text/plain"}}, "_bodyInit": {"_data": {"__collector": [Object], "blobId": "xxx", "name": "chat.txt", "offset": 0, "size": 42, "type": "text/plain"}}, "bodyUsed": false, "headers": {"map": {"cache-control": "no-store", "content-length": "42", "content-type": "text/plain; charset=utf-8", "date": "Sun, 21 May 2023 18:53:09 GMT", "expect-ct": "max-age=2592000, report-uri=\"https://sentry.repl.it/api/10/security/?sentry_key=xxx\"", "replit-cluster": "hacker", "strict-transport-security": "max-age=6123043; includeSubDomains", "uwebsockets": "20"}}, "ok": true, "status": 200, "statusText": "", "type": "default", "url": "https://xxx.luisafk.repl.co/chat"}

Duplicate of #25701 and #25910, but they were closed.

React Native Version

0.71.7

Output of npx react-native info

System:
    OS: macOS 12.6.3
    CPU: (8) x64 Intel(R) Core(TM) i7-6920HQ CPU @ 2.90GHz
    Memory: 346.30 MB / 16.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 19.7.0 - ~/.nvm/versions/node/v19.7.0/bin/node
    Yarn: 1.22.15 - ~/.nvm/versions/node/v19.7.0/bin/yarn
    npm: 9.5.0 - ~/.nvm/versions/node/v19.7.0/bin/npm
    Watchman: Not Found
  Managers:
    CocoaPods: Not Found
  SDKs:
    iOS SDK: Not Found
    Android SDK: Not Found
  IDEs:
    Android Studio: Not Found
    Xcode: /undefined - /usr/bin/xcodebuild
  Languages:
    Java: Not Found
  npmPackages:
    @react-native-community/cli: Not Found
    react: 18.2.0 => 18.2.0 
    react-native: 0.71.7 => 0.71.7 
    react-native-macos: Not Found
  npmGlobalPackages:
    *react-native*: Not Found

Steps to reproduce

Try the code example below.

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

const resp = await fetch('https://example.com');
const reader = resp.body.getReader();

首先在 React Native 0.71.7 上运行提供的 fetch/getReader 复现，并检查 Fetch API 响应体的行为。当 resp.body 可用，并且 resp.body.getReader() 能够在复现的响应上正常工作且不出现 undefined 错误时，即视为完成。