.Net: fix: adds support of allOf for OpenAPI dynamic payload generation

[baywet]

Motivation and Context

Current dynamic payload generation does not support allOf in OpenAPI.

Description

This recursively parses allOf entries to add all properties from parent schemas.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄