[flexiglass] Factor device provisioning for visibility

As a followup for ag/26072345, we're adding collection of device
provisioning state to the visibility evaluation.

The reason is that it's not enough to just look at whether FRP is
active, the system UI shade shouldn't be visible during the Setup Wizard
flow.

Fix: 322197941
Test: manually verified that sys UI is invisible in the setup wizard
Test: added a unit test for the startable
Test: expanded the integration test for Flexiglass
Flag: ACONFIG com.android.systemui.scene_container DEVELOPMENT
Change-Id: Ie74697253b36d6c64e424229b0628f7796b1b0d0