Migrate shared biometric icon logic, setup Secure Lock Device ViewModel

Migrate all BiometricPrompt icon-related logic into shared
BiometricAuthIconViewModel class and shared BiometricAuthIconUtils. This
includes the biometric iconAsset and content description, as well as
properties of the asset like shouldAnimateIconView and
shouldLoopIconView. This will allow this logic to be reused for the
biometric auth step of Secure Lock Device.

Also sets up the ViewModel for the eventual Secure Lock Device MVVM
structure, which will use an ExclusiveActivatable ViewModel and have the
Compose view observe its state and update the UI directly

Flag: android.security.secure_lock_device
Fixes: 398990889
Bug: 401645997
Test: atest AuthContainerViewTest
Test: atest BiometricAuthIconViewModelTest
Test: atest SecureLockDeviceInteractorTest
Test: atest PromptViewModelTest
Change-Id: I2d68c604e4a73e1815bd3b13fce440693bb16376