Patient $validate operation with Remote Terminology Service enabled returns 400 Bad Request

[volodymyr-korzh]

Patient $validate operation with Remote Terminology Service enabled returns 400 Bad Request response instead of 200 OK with a list of validation results.

To Reproduce

1. Add RemoteTerminologyServiceValidationSupport to ValidationSupportChain
2. Create Patient:

{
  "resourceType": "Patient",
  "active": true,
  "deceasedDateTime": "2015-02-14T13:42:00",
  "identifier": [ { "system": "urn:oid:1.2.36.146.595.217.0.1", "value": "12346" } ],
  "name": [ {
      "family": "smith",
      "given": [ "Jane" ]
  } ],
  "gender": "male",
  "birthDate": "1974-12-25",
  "telecom":[{"value":"581-309-1234"}]
}

3. Execute $validate operation on Patient instance:
   GET https://localhost:8000/Patient/1652/$validate
4. See 400 Bad Request response:

{
	"resourceType": "OperationOutcome",
	"issue": [
		{
			"severity": "error",
			"code": "invalid",
			"details": {
				"text": "[28909888-9c0c-4070-a15a-1e239b795686]: A code/system pair must be provided."
			},
			"diagnostics": "[28909888-9c0c-4070-a15a-1e239b795686]: A code/system pair must be provided."
		},
		{
			"severity": "information",
			"code": "informational",
			"diagnostics": "X-Request-Id: 822bdfe6-44c0-4341-9df6-5f5493f0e02b"
		}
	]
}

Expected behaviour
200 OK response with a list of validation results should be returned instead.