Fix UDFPS icon and progress while enrolling

fc343495 replaced onUiReady with
onUdfpsUiEvent which was only used by AIDL hals. onUdfpsUiEvent now
is responisble for the previous functionality and requesting the
enrollment icon + progress bar to be shown. The latter was missed for
HIDL hals, thus it wasn't visible.

Change-Id: I6cda3d3897fda350d506f777d3e85587ff04a0e3