appsecurity: update to use SigningInfo-based API.

The PackageInfo field exposed via GET_SIGNING_CERTIFICATES has been
changed, so the API tests checking that it provides the proper info
also need to be changed.

Bug: 74831530
Test: PkgInstallSignatureVerificationTest
Change-Id: I86842947c8a560f9818b2e4edce909dcdbf47869
1 file changed