New Pipeline: check initial keyguard state

The KeyguardCoordinator is responsible for paying attention to the
keyguard state and updating the SectionHeaderVisibilityProvider
correspondingly.

Instead of assuming we boot to the keyguard, and therefore that section
headers should be hidden, check the keyguard state and update the header
visibility when the coordinator attaches to the pipeline.

Bug: 216288085
Test: manual
Change-Id: Ic6e032043388070b4a162e57d84b9fe2ed6fbf46