Allow tablet/tv product variants override PackageInstaller

The PackageInstaller is in base_system.mk which is inherited by TV.
PackageInstaller_tv should overide it to avoid dual apps to be
installed.

Bug: 258572488
Test: make a TV device, check aritifacts, boot up.
Change-Id: I6b330fd9a908a75f033248872cc4a55843d97871