Switch to using checkDeviceTrust
In the UserInfo panel. This means we now use cross-signing
verifications in the UserInfoPanel so we can see our cross-signing
verifications working!
Lots more to do here: the remaining device.isVerified() calls in
UserInfoPanel are where it needs to be switched to verifying users
rather than devices, and of course we need to replace all the calls
to device.isVerified() with checkDeviceTrust everywhere else.
