Fix scrolling position not kept in Trusted Credentials

For example when changing display states.

Save view states to solve this issue.
 - Save current tab. (System / User)
 - Save group expanded state. (Personal / Work)
 - Save scrolling position of each group.

Also updated to ViewPager2 and updated the styles.

Bug: 204839552
Test: manual
Change-Id: Ibeda50b50e7dfd2ba071b75fe2aa88ef560f4c88

src/com/android/settings/TrustedCredentialsDialogBuilder.java

@@ -34,7 +34,7 @@ import android.widget.Spinner;
 import androidx.appcompat.app.AlertDialog;
 
 import com.android.internal.widget.LockPatternUtils;
-import com.android.settings.TrustedCredentialsSettings.CertHolder;
+import com.android.settings.TrustedCredentialsFragment.CertHolder;
 import com.android.settingslib.RestrictedLockUtils;
 
 import java.security.cert.X509Certificate;