UP-4223 Sticky profile mapping fails gracefully.

This is a tweak to #450 on the same theme as #454 .

Failing to honor a persisted profile selection is bad.  It's an error and should be logged for portal administrators to address.  However, it's probably better to press on falling back on some default profile selection instead of failing the entire user experience on account of uncertainty about whether a sticky profile selection has been applied.  So, fail gracefully on registry failure, as if user had no sticky profile selection.