Modify source stamp verifier to account for APK signature schemes V1, V2, and V3. The verifier would verify the signature schemes found in the APK. If the APK is signed using a signature scheme that does not have a corresponding verified source stamp signed digest, the source stamp is considered unverified. Bug: 158196850 Test: atest FrameworksCoreTests:SourceStampVerifierTest Change-Id: I07e3606a346b598d192771945335770ce964726e