Move NotificationStack to enableKeyguardCompose

Makes adjustments so that the NotificationStack into compose keyguard and adjust it to work
with the SharedNotificationContainer infra.

Bug: 301968149
Test: Ensure all views exist in KeyguardRootView. See notifications and
see that transition to notification shade is good.

Flag: ACONFIG com.android.systemui.enable_keyguard_compose DEVELOPMENT

Change-Id: I4a75218652aa6c75661a9875a61db6f927ced7e4