Refactor/clean and add function

[WillemZeiler]

PR Description:

Adjustments to the JS

Refactored

• Updated the function comment block to follow ServiceNow best practices.
• Renamed pFields and fields to allFields and editableFields for clarity.
• Replaced inline indexOf() checks with a reusable helper function shouldClear().

Added

• Added validation to ensure dontClearFieldsArray is a valid array before use.
• Introduced clearedFields array to track which fields were cleared.
• Implemented logic to return the list of cleared fields at the end of the function.

Adjustments to the readme

• Updated readme to better describe existing functionality and included the new functionality.
• Also included a more descriptive example.

Pull Request Checklist

Overview

• Put an x inside of the square brackets to check each item.
• I have read and understood the CONTRIBUTING.md guidelines
• My pull request has a descriptive title that accurately reflects the changes and the description has been filled in above.
• I've included only files relevant to the changes described in the PR title and description
• I've created a new branch in my forked repository for this contribution

Code Quality

• My code is relevant to ServiceNow developers
• My code snippets expand meaningfully on official ServiceNow documentation (if applicable)
• I've disclosed use of ES2021 features (if applicable)
• I've tested my code snippets in a ServiceNow environment (where possible)

Repository Structure Compliance

• I've placed my code snippet(s) in one of the required top-level categories:
  • Core ServiceNow APIs/
  • Server-Side Components/
  • Client-Side Components/
  • Modern Development/
  • Integration/
  • Specialized Areas/
• I've used appropriate sub-categories within the top-level categories
• Each code snippet has its own folder with a descriptive name

Documentation

• I've included a README.md file for each code snippet
• The README.md includes:
  • Description of the code snippet functionality
  • Usage instructions or examples
  • Any prerequisites or dependencies
  • (Optional) Screenshots or diagrams if helpful

Restrictions

• My PR does not include XML exports of ServiceNow records
• My PR does not contain sensitive information (passwords, API keys, tokens)
• My PR does not include changes that fall outside the described scope

[bird-03]

@WillemZeiler
Thanks for your contribution to Catalog Client Script . Keeping the script scope for classic UI and Serviceportal/mobile is great consideration and it is often ignored

Keep Contributing as I will be reviewing the PRs .....Hahaha ( Happy Hacking)