Retrieve direct boot aware activities.

Immediately on boot (before a user is unlocked), PackageManager only
returns components that are direct boot aware. If we don't specify that
direct boot unaware components be returned as well, then ASC will think
all system apps are headless.

Also switching the cache from an ArrayMap to an ArraySet because there's
no need for the boolean value.

Bug: 155761007
Test: manually verify that apps with launcher activities aren't in the headless app list
Test: atest CtsUsageStatsTestCases:UsageStatsTest
Test: atest FrameworksServicesTests:AppIdleHistoryTests
Test: atest FrameworksServicesTests:AppStandbyControllerTests
Change-Id: Ieec648226d0d5a32197647af286c2cd4c167dd8b