Fix: JSONResponse helper to preserve original onResponse behavior (Fixes #5042)

[myrepojuly]

Motivation/Description of the PR

• Description of this PR, which problem it solves: Problem:
  The current implementation overrides any custom onResponse handler that may have already been set in the user's configuration, causing their logic to be lost.

Suggested Fix:
Preserve the original onResponse handler by wrapping it, rather than replacing it:

• Resolves #issueId (if applicable): Fixes REST helper config: onResponse provided in config does not work #5042

Applicable helpers:

• Playwright
• Puppeteer
• WebDriver
• REST
• FileHelper
• Appium
• TestCafe

Applicable plugins:

• allure
• autoDelay
• autoLogin
• customLocator
• pauseOnFail
• coverage
• retryFailedStep
• screenshotOnFail
• selenoid
• stepByStepReport
• stepTimeout
• wdio
• subtitles

Type of change

• 🔥 Breaking changes
• 🚀 New functionality
• 🐛 Bug fix
• 🧹 Chore
• 📋 Documentation changes/updates
• ♨️ Hot fix
• 🔨 Markdown files fix - not related to source code
• 💅 Polish code

Checklist:

• Tests have been added
• Documentation has been added (Run npm run docs)
• Lint checking (Run npm run lint)
• Local tests are passed (Run npm test)

[Copilot]

Pull Request Overview

This PR fixes a bug in the JSONResponse helper where setting the onResponse handler was overriding any existing custom onResponse handler in the user's configuration. The fix preserves the original onResponse behavior by wrapping it instead of replacing it.

Key changes:

• Preserve existing onResponse handlers by storing and calling the original function
• Maintain backward compatibility while fixing the override issue

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[kobenguyent]

Please add tests if that's possible. Thanks.

[myrepojuly]

@kobenguyent - I’ve added tests under ./test/unit/helper/, but some existing tests are failing, and I can’t push.
Is it okay to use --no-verify to bypass the husky's pre-push check?

430 passing (16s)
1 pending
3 failing

1) FileSystem
   should check file contents:
   expected contents of fs_sample.txt to equal:
   "A simple file
   for FileSystem helper
   test"

2) HTML module
   #splitByChunks
   should cut long HTMLs into chunks and add paths into them:
   AssertionError: expected array length of 21, but got 22

3) utils
   #screenshotOutputFolder
   returns the joined filename for filename only:
   AssertionError: expected path to be relative, but got absolute Windows path

[kobenguyent]

@myrepojuly i guess that's fine as we would run tests on GitHub anyway.

[myrepojuly]

@kobenguyent - thank you.. Added the unit tests...