Use package from sipper if default is null

Use package from sipper if default is null

The BatteryEntry need a background thread to update the
package name and icon. However in InstalledAppDetails we
don't have this thread and it is unnecessary because we
already has the package name.

This cl:
1. Use the mPackageName from InstalledAppDetails directly in
BatteryEntry
2. Double check the defaultPackageName in AdvancedPowerUsageDetail,
use packageName from sipper if default is null

Bug: 64127162
Test: RunSettingsRoboTests

Change-Id: I5d21afca17f177817976758c28ed86b3a10e95eb
Merged-In: I5d21afca17f177817976758c28ed86b3a10e95eb