Validator's error message is not showing on the Raise a Request screen in the Customer Portal

Problem

The dedicated error message configured for JMWE validators are not showing on the Portal's request form.

Steps to reproduce the issue

1. With a compatible version of the Jira Misc Workflow Extensions add-on installed, add a validator and specify a unique error message to be displayed if the input is not provided for the transition. Example configuration:
   
2. Raise the request via Portal without providing the required input and observe the error.
3. Raise the request via Jira without providing the required input and observe the error.

Expected Result

The dedicated error message is displayed correctly on the Portal's request form just like how it is on the Jira's Create Issue screen, telling users what is expected or which requirements are not fulfilled.

Actual Result

• On the Portal, only the generic error message is displayed while the dedicated error message is missing.
  
• On the Jira's Create Issue screen, the dedicated error message is showing correctly.
  

Notes

This is not affecting all validators of other add-ons. Tested the same with Suite Utilities for Jira's Date Expression Compare validator and the error message is showing as expected.

Related Bug ticket: JSDSERVER-5882 Misleading validator's error message appears for requests failed to be created for the wrong error message displayed when a request cannot be raised due to permission error.