Reorder the passkey username & displayname

1) displayname on top if one is available, username on second line.
2) username on top if displayname is not available.
3) don't show username on second line if username == displayname

Bug: 273609955
Test: manual (see bug for screenshots)
Change-Id: If3d052c01233119e9194f602739cbe8033090e7d