The example of the usage of LoginWithGoogleAccount for javascript uses the (supposedly) old AccessToken property:
https://api.playfab.com/docs/tutorials/landing-players/google-html5
This property doesn't exist in the documentation:
Also, now the recommended method to login with google is using the ServerAuthCode, but there's only an example of that using Google Play Games to retrieve the ServerAuthCode.
It's been impossible to me to make the login work with plain JavaScript using the ServerAuthCode. I think that the tutorial should have been updated before removing the AccessToken.