Use an Android Feature flag to guard Pia V2

Bug: 182205982
Bug: 312787400
Test: adb shell device_config put package_manager_service android.content.pm.use_pia_v2 true && adb reboot
Install an APK or uninstall an APK
Test: presubmit

Change-Id: I8c206bbaff5d8607d97fe426e0154d3642aba310