Android client: ask for correct project account identifier

[davidpanderson]

When you attach to a project, it shows:

eMail: ____ Name: ____ Password: ____

It should say Email address: ___ Password: ____

if the project identifies accounts by email addr (all except WCG) and

User name: ____ Password: ____

for WCG

[pschoefer]

WCG switched to the standard email-based login four years ago (see https://worldcommunitygrid.org/about_us/article.s?articleId=602), so the special treatment is not required anymore.

[AenBleidd]

@pschoefer, even if this is currently true, there is still a possibility from the server side to configure it differently from the default, and thus we should handle this on the client side appropriately