Update AppListRepository getSystemPackageNames

Since Instant Apps never system, no need for param showInstantApps.

Also correct the test result, since "home app" and "app in launcher"
will not be returned from this function.

Bug: 280280596
Test: Unit Tests
Change-Id: I2ae17ecaa24780fb2f0c896e84176fc16ccf7de0
3 files changed