Add support to configure double line clock in lockscreen [1/2]

Add an override that can be used to configure the default state
of double line clock in lock screen.

Co-authored-by: Luca Weiss <luca.weiss@fairphone.com>
Bug: 277244307
Test: atest KeyguardClockSwitchControllerTest
Change-Id: I35d5b2807befe253ba327690fdcbc39af3bcfb37
Merged-In: I35d5b2807befe253ba327690fdcbc39af3bcfb37