Verify PackageManagerShellCommand caller is shell

Also verifies that printing domain verification state asserts that
the caller is an approved querent, to match the
getDomainVerificationInfo Java API.

Bug: 200035185

Test: atest DomainVerificationEnforcerTest

Change-Id: I1daeeee9d44e54e21643fe6253ff8012dbe364b8
3 files changed