Do not show keyguard clock when communal mode is active.

This changelist hides the clock (part of the KeyguardStatusView)
when communal mode is shown on the keyguard.

Bug: 196885298
Test: atest KeyguardVisibilityHelperTest
Test: atest NotificationPanelViewTest#testKeyguardStatusViewUpdatedWithCommunalPresence
Change-Id: I488f51526babb5bc404a1dea1572ed43cd28372c