Swagger ModelValidation erroneously fails when required x-ms-secret properties are omitted from responses in examples

From the [x-ms-secret documentation](https://github.com/Azure/autorest/tree/main/docs/extensions#x-ms-secret):

> When a property is modeled as both "required" and "x-ms-secret": true, which means that this property must not exist in the response but has to be present in request.

The Swagger ModelValidation pipeline fails for this scenario, erroneously flagging properties that match this scenario that are missing from example responses as errors, e.g.:
https://github.com/Azure/azure-rest-api-specs/pull/18645/checks?check_run_id=6586657182