Login dialog pops open for a split second when token already present

[mpost]

Logging in while entering the credentials works as expected. Next i log out and log in again while the credentials are locally present, the login dialog pops open and disappears instantly. That is not expected. The dialog could appear if multiple google accounts could be chosen from. See #40.

[enyo]

I have the same issue but it also happens with the native JavaScript library provided by Google. So I assume that this s not dart-google-oauth2-library specific.