Update incompleteChkListShowErrMsg.js to validate checklist completion before status change

[Shweyy123]

README.md

📌 Description

This Business Rule enforces checklist compliance by preventing an incident record from transitioning to the "In Progress" state if any associated checklist items remain incomplete.

By validating checklist completion before the update, this rule ensures agents fully address all predefined tasks, validations, or data collection steps before progressing the incident’s workflow. If even one checklist item is unchecked, the system will block the state change and display a clear, user-friendly error message.

This logic supports stronger process adherence, improves data quality, and reduces the risk of prematurely working on tickets without meeting preconditions—ideal for ITSM environments that require strict task completion before action.

[WillemZeiler]

Thank you for your contribution. However, it doesn’t comply with our contributing guidelines. As a reminder, the general requirements (as outlined in the CONTRIBUTING.md file) are the following: follow the folder+subfolder+snippetfolder guidelines and include a readme.md file explaining what the code snippet does. Review your contribution against the guidelines and make the necessary adjustments. Closing this for now. Once you make additional changes, feel free to re-open this Pull Request or create a new one.