Update expectations around APEX manifests in `art_apex_test.py`.

Recent changes broke ART's Host APEX checks. Adjust and increase them by:
- checking for the Protocol Buffers APEX manifest (in all APEXes);
- no longer checking for the (Android Q compatible) JSON APEX
  manifest (even in target APEXes).

Test: art/build/apex/runtests.sh
Bug: 143654022
Bug: 139277987
Change-Id: I4afc23d56fe90aaf447f334bde3bc0117f12d1aa
1 file changed