Run apex_sepolicy_tests with erofs apexes

This turns on apex_sepolicy_tests for erofs apexes. The test now uses
`apex-ls` (a new tool to print security contexts for apex contents).

Bug: 353896817
Test: OVERRIDE_PRODUCT_DEFAULT_APEX_PAYLOAD_TYPE=erofs m run_apex_sepolicy_tests
Change-Id: Ia42d0641be7a5007fb73337257893235f9a98f22