keepalive onPingResponse subscribe response doesnt work right

[hakim-dc]

[X] bug report

Current behavior
this subscription must return the web-service response used to update session expiry time
"keepalive.onPingResponse.subscribe(response => console.log(response);"

Expected behavior
after subscribe onPingResponce the response.status must return the status of invoked
http request in "response.status"
example: 200 for success

Minimal reproduction of the problem with instructions
the main problem is that this subscription always return first a response that contain a type equal to 0
after that it return the real webservice response (response.status not null ) for each keepalive webservice
pingRequest but in the other hand when the webservise return request.status different to 200
(not success) we get first also a response that contain a type equal to 0 and no other response.

What is the motivation / use case for changing the behavior?
my expected behavior is that method return only response that contain the http request status in case of
success or fail of web-service invocation and remove the responce that contain type equal to 0
"response.type = 0"

Please tell us about your environment:
Ubuntu, visualCode, npm

• @ng-idle version: 6.0.0-beta.3

• Angular version: 6.x

• Browser: all

• Language: TypeScript 2.7.2

• Node: node --version = v10.9.0