[Dual Shade] Shared element transition: lockscreen clock and shade clock

Bug: 384730787
Bug: 376659778
Test: Manually tested by opening and closing both the notifications
 shade and quick settings shade on a folded and unfolded device, and
 confirming that the shade clock is rendered in a shared element
 transition with lockscreen clock (and translated from/to top when
 transitioning over Gone scene).
Flag: com.android.systemui.dual_shade
Change-Id: I635e7d772095fc724978f0dc76c36987ed056a7c