Documentation: Update evaluation endpoint details

[AkhileshNegi]

Is your feature request related to a problem?
The current Postman documentation for the evaluation endpoint is outdated, missing details, and ambiguous, which can confuse users.

Describe the solution you'd like

• Review and update the Postman collection for the evaluation endpoint, including request/response schemas.
• Improve clarity and detail in documentation for all evaluation-related requests.
• Add examples and use cases (sample payloads, expected responses, error scenarios).
• Ensure consistent terminology, parameter naming, and structure in the documentation.
• Verify correct documentation of authentication, headers, and environment variables.

Original issue

Is your feature request related to a problem?
The current Postman documentation for the evaluation endpoint needs to be reviewed to identify any outdated, missing, or ambiguous
information that could lead to confusion for users.

Describe the solution you'd like

• Review the existing Postman collection for the evaluation endpoint and update request/response schemas where needed.
• Improve documentation clarity and detail for all evaluation-related requests.
• Include examples and use cases (sample payloads, expected responses, error scenarios) for better understanding.
• Ensure consistency in terminology, parameter naming, and structure throughout the evaluation endpoint documentation.
• Verify that authentication, headers, and environment variables are documented correctly.

Why is this enhancement needed?
Enhancing the Postman documentation for the evaluation endpoint will improve usability, reduce user confusion when integrating or testing evaluations, and lead to a better overall developer experience.