Add permission checks for Verification API calls

Ensure that only applications with
android.Manifest.permission.PACKAGE_VERIFICATION_AGENT can call application
verification APIs, like PackageManager.verifyPendingInstall and
PackageManager.extendVerificationTimeout

Bug: 7049083
Change-Id: I5fc28b37e864d67cd319a1ed9d03a90dd15ad052
4 files changed