Add logging when signature is either not found or doesn't pass
verification

Note: InvalidKeyExceptions may be thrown for other reasons (e.g.
signature algorithm not matching), hence the addition of a new Exception
to specify when the public key is missing.

Flag: com.android.net.ct.flags.certificate_transparency_service
Fixes: 384931263
Bug: 378626065
Test: atest NetworkSecurityUnitTests
Change-Id: I67341b1e2d169cf634e45ca84eb24e3a1f6d887e
4 files changed