Handle cancellation properly for setDeviceCredentialAllowed(true)

Keep the current auth session until ConfirmDeviceCredential succeeds
or fails. ConfirmDeviceCredential's BP and LSKF screens can be canceled
now.

Bug: 123378871
Bug: 128747871

Test: With modified BiometricPromptDemo, ConfirmDeviceCredential's
      BiometricPrompt and LSKF screens can be canceled

Change-Id: Icaf3f0c55b07fd138a2ee9d214941ea83408f0ee