Bring back lock icon w/ wallpaper color on LS

Current POR is to only hide the lock icon when udfps is enrolled

On the LS, change the color of the lock icon based on the wallpaper
color, else use textColorPrimary for the bouncer where the bouncer
is background is white.

Test: manual
Bug: 170228350
Change-Id: Iddedb3c7338f7a995e4787d1ec55bbee960b780d