Move clock centering and size logic from npvc.

Move centering and sie logic from npvc to clock interactor. Add respective tests.
Tests apply to scene container and non scene container scenarios.

Test: Observe clock appearance changes in flexiglass
Fixes: 330666222
Flag: ACONFIG com.android.systemui.scene_container DEVELOPMENT
Change-Id: I35efbe2429d4b760cb71d4ed568732a6365c7b3b