Make system item has a consistent name.

In battery settings, the system item contains many packages. In old
behaviour it will use the first package(which has legal name and icon)
to represent this item. This behaviour is not consistent.

In this cl, we always use package "android" to extract name and icon
if it is system item.

Bug: 65090883
Test: RunSettingsRoboTests
Change-Id: Ibb7f85c06ab1745867f1eaa666cea32c8d3295a6