feat: Updated behaviour of AdditionalProperties when owning OptionalPropery

[Himenon]

Summary

GitHub OpenAPI Schemas has below

schemas:
  integration:
    type: object
    properties:
        permissions:
          description: The set of permissions for the GitHub app
          type: object
          properties:
            issues:
              type: string
            checks:
              type: string
            metadata:
              type: string
            contents:
              type: string
            deployments:
              type: string
          additionalProperties:
            type: string
          example:
            issues: read
            deployments: write

Test Plan