CDD: Require secure storage of lock screen credentials

- With credential-based Factory Reset Protection, the
credential handle is stored on an unencrypted partition. To maintain
security guarantees, implementations must make sure that the handle
does not leak information about the credential.

Bug: 64209214
Test: n/a
Change-Id: I55f15cc75502016824d9307c03d947c4041744b0
1 file changed