ComposeClock: Support show seconds within the clock

We want to continue support show seconds in the compose clock. This
requires changing the flow in the ClockInteractor to emits every second
instead of every minute when necessary.

Right now, it is still guarded behind the TunerService.

Bug: 390204943
Flag: com.android.systemui.clock_modernization
Test: ClockViewModelTest, ClockInteractorTest
Change-Id: Ice13be3e3f755c70117b937c24acae9f748f497b