Prevents uninstalled packages from being added to the DB.

Apps trying to set the standby bucket for a package that was uninstalled
will now be blocked to prevent uninstalled package entries from
appearing in the App Standby DB.

Bug: 116190365
Test: atest com.android.server.usage.AppIdleHistoryTests
Test: atest com.android.server.usage.AppStandbyControllerTests
Test: atest cts/tests/tests/app.usage/src/android/app/usage/cts/UsageStatsTest.java
Test: atest vendor/xts/gts-tests/tests/usagestats/src/com/google/android/usagestats/gts/UsageStatsTests.java
Change-Id: If421c46f3459eced78ae260e88749022ed5cf7a2