Do not show key entries used for user authentication flow

Bug: 33126414
Test: Enable new authentication flow; go to user credentials in Settings
      observe no entries related to user authentication are shown.
Change-Id: I62e5796cc73213b23ca7809a77082350a883fbee

src/com/android/settings/UserCredentialsSettings.java

@@ -264,11 +264,17 @@ public class UserCredentialsSettings extends OptionsMenuFragment implements OnIt
             final SortedMap<String, Credential> aliasMap = new TreeMap<>();
             for (final Credential.Type type : Credential.Type.values()) {
                 for (final String alias : keyStore.list(type.prefix, uid)) {
+                    if (UserHandle.getAppId(uid) == Process.SYSTEM_UID) {
                         // Do not show work profile keys in user credentials
                         if (alias.startsWith(LockPatternUtils.PROFILE_KEY_NAME_ENCRYPT) ||
                                 alias.startsWith(LockPatternUtils.PROFILE_KEY_NAME_DECRYPT)) {
                             continue;
                         }
+                        // Do not show synthetic password keys in user credential
+                        if (alias.startsWith(LockPatternUtils.SYNTHETIC_PASSWORD_KEY_PREFIX)) {
+                            continue;
+                        }
+                    }
                     Credential c = aliasMap.get(alias);
                     if (c == null) {
                         c = new Credential(alias, uid);