Fix regression in the check session service

[Guerric-P]

In this commit: 5c57084900237245e0fe3b7db58cc188f4f5fe75 the code was refactored in order to retrieve the reference to the browser's global variables via Angular's dependency injection.

In this line: 5c57084#diff-dec315070d26d82195b08309ea5550cfd8d36e230b58ab9ddb59a401fe9ff3a4L185, window was replaced with this.document which is wrong because the events of type message are being emitted by window, not document.

That prevents the library from receiving response message events from the iframe, which causes these errors in the console:

[ERROR] 0-app- CheckSession - OidcSecurityCheckSession not receiving check session response messages. Outstanding messages: '12'. Server unreachable?

It also very probably prevents the check session mechanism from working at all.

My pull request fixes this by replacing this.document with this.document.defaultView, an actual reference to window.
It fixes #1428

[FabianGosebrink]

Thanks!!!

[Guerric-P]

You're welcome! May I ask when do you plan to release a version?

[FabianGosebrink]

I think we can do this in the next days. Thanks!

[Guerric-P]

Ok 👌 thank you too!