Use aconfig device_entry_udfps_refactor flag

Instead of legacy refactor_udfps_keyguard_views flag.

Flag: ACONFIG com.android.systemui.device_entry_udfps_refactor DEVELOPMENT
Test: atest SystemUITests
Bug: 279440316
Bug: 305234447

Change-Id: Icccb5b4cc0f371adc2f6d7492850e344f0e4ea2a