Wrong callback after login flow

[glciampaglia]

The recent testing showed that in some instances Twitter will not load the correct callback URL at the end of the login flow; instead it will load Twitter itself. This seems like a bug with Twitter, which may be affecting other people or may be only temporary. Since this is not something we can fix ourselves, and since we do not know how frequent it is, we will monitor the soft launch and see if people report having this issue.