Arm-Validator does not enforce 200 and 201 on PUT contract

Also if the response code is `204`, then according to HttpSpec, it should not have any content. It does not even catch that.
**Referred Spec**
https://github.com/Azure/azure-rest-api-specs/blob/master/specification/apimanagement/resource-manager/Microsoft.ApiManagement/stable/2017-03-01/apimportalsettings.json#L209

Start with the referenced specification file, apimportalsettings.json, at the linked PUT contract. Trace the validator entry point that checks response status codes and 204 responses, then verify that the contract rejects statuses other than 200 or 201 for PUT and rejects content on 204 responses.

Written by the indexing model from the issue text.