Remove flag report_primary_auth_attempts

Since this flag was launched, remove it and make the corresponding code
unconditional.

Bug: 285053096
Test: atest FrameworksServicesTests:com.android.server.locksettings
Flag: EXEMPT removing android.security.report_primary_auth_attempts
Change-Id: I47bb87a4f14873b1edcd28be848bc258809c86e2