serveStaticJson and serveStaticText failing default CORS tests in dev-middleware

Description

During the development of the dev-middleware package, the automated tests for serveStaticJson and serveStaticText fail because they expect default Access-Control-Allow-Origin headers in the response. The current implementation no longer includes these headers by default.

This causes test failures even though the main functionality of serving JSON or text works correctly.

Steps to reproduce

1. Clone the repository.

2 . Run: yarn jest packages/dev-middleware/src/tests/ServerUtils-test.js --runInBand --verbose

3. Observe that the tests for serveStaticJson and serveStaticText fail due to missing CORS headers.

Expected behavior:
Tests should pass or be updated to reflect the current implementation.

Actual behavior:
Tests fail because the response does not include "Access-Control-Allow-Origin": "*" as previously expected.

React Native Version

0.82.1

Affected Platforms

Build - MacOS

Output of npx @react-native-community/cli info

System:
  OS: macOS 14.1.1
  CPU: (10) arm64 Apple M1 Max
  Memory: 417.81 MB / 64.00 GB
  Shell: 5.9 - /bin/zsh
Binaries:
  Node: 22.14.0
  Yarn: 1.22.22
  npm: 10.9.4
SDKs:
  iOS SDK: 17A400
  Android SDK: 33
npmPackages:
  react: 19.1.1
  react-native: 0.82.1

Stacktrace or Logs

FAIL  packages/dev-middleware/src/__tests__/ServerUtils-test.js
  ServerUtils
    ✕ serveStaticJson sets CORS header (285 ms)
    ✕ serveStaticText sets CORS header
    ✓ baseUrlForServer returns correct URL (1 ms)

  ● ServerUtils › serveStaticJson sets CORS header
    expect(jest.fn()).toHaveBeenCalledWith(...expected)
    Expected: 200, ObjectContaining {"Access-Control-Allow-Origin": "*", "Content-Type": "application/json"}
    Received: 200, {"Content-Type": "application/json"}

  ● ServerUtils › serveStaticText sets CORS header
    expect(jest.fn()).toHaveBeenCalledWith(...expected)
    Expected: 200, ObjectContaining {"Access-Control-Allow-Origin": "*", "Content-Type": "text/plain"}
    Received: 200, {"Content-Type": "text/plain"}

MANDATORY Reproducer

https://github.com/THE-Amrit-mahto-05/react-native-dev-middleware-repo.git

Screenshots and Videos

https://github.com/user-attachments/assets/bbec821b-f0a8-42a3-be58-a17fdceabf08

从 packages/dev-middleware/src/tests/ServerUtils-test.js 开始，并运行报告中的 Yarn Jest 命令。检查 serveStaticJson 和 serveStaticText，以确定缺失的 CORS 标头是否反映了预期的契约；完成的标准是测试和实现一致，并且目标测试文件通过。