Fingerprint: call onRemovalSucceeded with # of remaining templates.

The onRemoved() callback from fingerprint daemon provides a "remaining"
parameter which contains the number of fingerprint templates yet to be
removed in the current removal operation. This is especially useful when
a group is removed, as remaining == 0 indicates the end of the group
removal.

In this CL, we wire up FingerprintManager so that the "remaining"
parameter gets passed to RemovalCallback#onRemovalSucceeded(). This
would allow clients like Settings to make use of the information.

Bug: 37938345
Test: manual, both with and without work profile
Change-Id: Idf46ef42e1d178cd3dc267aaf4219f03e27be766