Remove incorrect assumption.

The initial assumption was that PACKAGE_RESTARTED meant that the app
would be put into the stopped state and be kept in the stopped state
until the PACKAGE_UNSTOPPED broadcast was sent. However, there are cases
where the PACKAGE_RESTARTED broadcast is sent but the app is not put and
kept in the stopped state (eg. clearing app data). Change the logic to
no longer assume that PACKAGE_RESTARTED means the app is put and kept in
the stopped state.

Bug: 315171674
Test: atest android.permissionui.cts.SafetyLabelChangesJobServiceTest#runNotificationJob_packageSourceUnspecified_updatesSafetyLabelHistoryForApps
Test: atest FrameworksMockingServicesTests:BackgroundJobsControllerTest
Change-Id: I23efa966b4963ca1777bdac58bbdad2f250c4984