Revert "Copy startup & callback mechanism from fingerprint to face service."

This reverts commit 294f4a1e79e5989ba441e88b6f2c2c1bcc9e7a2e.

Reason for revert: b/242845336 (a few cts tests seem to pass on device locally but fail on cf postsubmit)

Change-Id: Icf36d403f96fc7a24d5191e7f43f43354a32b54f
31 files changed