Show a message on focussed display if biometric prompt is triggered from a non-default display

Bug: 419799860
Flag: com.android.window.flags.show_biometric_prompt_secondary_display_toast
Test: atest com.android.systemui.biometrics.AuthControllerTest

Change-Id: I1f7da07b80bba7c6b3a13d2d51995f0f1b6a1d8b