Added Form Dirty State Manager snippet for preventing data loss

[BEASTSHRIRAM]

PR Description:

This snippet provides a reusable client-side script that prevents users from accidentally losing unsaved form changes in ServiceNow.
Features:

• Automatic detection of all field changes on the form
• Warns users before leaving the page with unsaved changes
• Visual indicator showing form state
• Auto-reset after successful save
• Simple one-line initialization
  Use Cases:
• Multi-step forms where users might accidentally navigate away
• Long forms where data entry takes significant time
• Critical data entry screens where data loss would be problematic

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

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• 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]

Thanks for your contribution!

This looks good to prevent users' loss of data before navigating away or closing the form.

Recommend to check other 2 project as well and keep contributing.

Happy Hacking!