Places the CommonResponse struct at the *end* of all IAM responses. (#8537)

* Places the CommonResponse struct at the end of all IAM responses, rather than the start.

* iam: fix error response request id layout

* iam: add XML ordering regression test

* iam: share request id generation

---------

Co-authored-by: Aaron Segal <aaron.segal@rpsolutions.com>
Co-authored-by: Chris Lu <chris.lu@gmail.com>

weed/s3api/s3api_embedded_iam.go

@@ -162,6 +162,7 @@ func newIamErrorResponse(errCode string, errMsg string) iamErrorResponse {
 	errorResp.Error.Type = "Sender"
 	errorResp.Error.Code = &errCode
 	errorResp.Error.Message = &errMsg
+	errorResp.SetRequestId()
 	return errorResp
 }
 

weed/s3api/s3api_embedded_iam_test.go

@@ -1214,6 +1214,8 @@ func TestEmbeddedIamNotImplementedAction(t *testing.T) {
 	apiRouter.ServeHTTP(rr, req)
 
 	assert.Equal(t, http.StatusNotImplemented, rr.Code)
+	assert.Contains(t, rr.Body.String(), "<RequestId>")
+	assert.NotContains(t, rr.Body.String(), "<ResponseMetadata>")
 }
 
 // TestGetPolicyDocument tests parsing of policy documents