Use Lazy BioUnlockController in DozeServiceHost.

Use Lazy BiometricUnlockController in DozeServiceHost instead of
assigning its result to a member field after initialization. It
appears as though, in some cases, the DozeServiceHost gets used
before it is initialized, meaning that the BiometricUnlockController
member field would be null.

Fixes: 152187753
Test: atest SystemUITests
Change-Id: Ic1a31ded99b1cd07e25f9da530bcf155722bbe6a