Remove pieces of device entry flag part #3

f note, a lot of tests from UdfpsControllerTest
were not running with the flag enabled. Opened a bug to
perhaps restore some of these, as the code is maybe active.
See b/372952178

Bug: 279440316
Test: atest SystemUITests
Flag: com.android.systemui.device_entry_udfps_refactor
Change-Id: I702bfc48bc765320dd66e4dc9c7a6c1cc6a6a7a2