[flexiglass] Rewrite Shade Header in Compose and migrate it to flexiglass

Reimplemented the shade header UI in Compose and inserted it into the Shade and QS scenes. The day/date view and ShadeCarrierGroup were rewritten; all other children were dropped in as AndroidViews for now. The only visual difference between the new implementation and the old is the lack of the Clock animation during the Shade -> QS transition, which is blocked by the dynamics framework not yet supporting shared text animations.

Additionally, camera cutout handling for the collapsed state has not yet been implemented.

Bug: 296251116
Test: new viewmodel tests
Test: see video attached to bug
Change-Id: I7bbc20ecc90c9c4c1b3b82d9e054b1707890cd35