Continue flag work for MGF1 Digest setter

Rename the MGF1 Digest Setter flag to "v2" so it can
be set as a read-only flag.

Test: atest CtsWebkitTestCases:android.webkit.cts.WebViewSslTest#testProceedClientCertRequestKeyWithAndroidKeystoreKey CtsKeystoreTestCases:android.keystore.cts.CipherTest#testKatBasicWithDifferentProviders CtsKeystoreWycheproofTestCases:RsaOaepTest
Bug: 308378912
Bug: 308069562

Change-Id: Id46ffc14f2b02cb51cd7df39f30ea757073a2144
6 files changed