Can't edit/update the details that login.launchpad.net sends

[Matthew Paul Thomas]

login.launchpad.net sends a variety of personal information to RPs, but doesn't let me update any of that information. (In my case, quite a lot of it is now out of date.)

I should be able to update the information from login.launchpad.net. Ideally it should be possible to do this as a detour while authenticating to an RP, because that's when I'll notice that the information is out of date. The authentication should continue once I've finished.

[Previously mentioned in bug 132890.]