Don't save password metrics to disk.

On FBE devices, don't save the metrics to disk but compute them when the
password is first entered and only store them in RAM.

Merged-in: 5daf273b7e3272269c53eda20ce494d0e7a365b5
Bug: 32793550
Change-Id: Icee7f615167761177b224b342970a36c7d90f6ba
5 files changed