Changes to Retrieve event

added subschema #1: Service Event Details to the details response property oneOf list for the response status 200

the id response's property type changed from no type to string for status 200

added the new disk_snapshot_restored enum value to the type response property for the response status 200

added the optional property code to the response with the 400 status

added the optional property code to the response with the 401 status

added the optional property code to the response with the 403 status

added the optional property code to the response with the 404 status

added the optional property code to the response with the 406 status

added the optional property code to the response with the 410 status

added the optional property code to the response with the 429 status

added the optional property code to the response with the 500 status

added the optional property code to the response with the 503 status

removed details from the details response property oneOf list for the response status 200

the id response's property pattern ^evt-[0-9a-z]{20}$ was added for the status 200