[DO NOT MERGE]Revert "Relax minimum signature scheme version for apps on system partition"

This reverts commit b71e3989.

Revert reason: System apps should now have uncompressed dex / library
files in their APKs and should be able to satisfy the minimum V2
signature requirement when targeting API level 30+.

Fixes: 215046612
Test: Manually verified V1 only signed APK targeting API level 30
      on the system image failed to verify.
Change-Id: Ic53d2a3614e7dff4e4bfe18561d3dfbb665bbcb2