Show notifications when dreaming with overlay only

Previously notifications are shown when any type of dream is active,
including doze. This is not the intended behavior. They should only
show when dreams with overlay are active, because the status bar is
rendered on the overlay.

Test: atest KeyguardUpdateMonitorTest
Test: atest KeyguardNotificationVisibilityProviderTest
Test: verified call chip showing over dream
Test: verified no onMeasure regression by running locally:
atest systemui-splitscreen-4-jank-suite \
   --request-upload-result \
   -- --enable-module-dynamic-download \
   --module-arg systemui-splitscreen-4-jank-suite:strict-include-metric-filter:'perfetto_android_notifications_blocking_call-blocking_calls-name-NotificationStackScrollLayout#onMeasure-cnt-mean' \
   --test-arg com.android.tradefed.testtype.AndroidJUnitTest:class:android.platform.test.scenario.sysui.splitscreen.UnlockKeyguardToSplitScreenGesturalNavPortraitMicrobenchmark
Bug: 425790289
Flag: com.android.systemui.ongoing_activity_chips_on_dream

Change-Id: Ib24a60701c88fe7cc54870396aa389eb7222f675