API documentation for new Message Testing Feature

[victor-chaparro]

Problem Statement

The Swagger documentation for the message testing API needs to be updated to improve clarity and usability.

What You Need to Know

The existing documentation for the reports/testing/test API should be revised to ensure it clearly explains its purpose and usage.

The current documentation is located at:
prime-router/docs/api/reports.yml

Acceptance Criteria

• [ ] Message testing API is updated