Prompt credentials for installing/deleting sounds

Actually we probably want to confirm credentials in all locked cases
not just when starting the user -- fewer corners to special case.

Fix: 34734809
Test: manual. set a work profile lock, screen off/on, open sound settings, try to set a work ringtone. first attempt should prompt for credentials, second attempt should not until next screen-off.
Change-Id: I1fea94f3b0d1b768b22741b887d9891f5e318549

src/com/android/settings/DefaultRingtonePreference.java

@@ -46,7 +46,7 @@ public class DefaultRingtonePreference extends RingtonePreference {
     @Override
     public void performClick() {
         if (mUserId != UserHandle.USER_CURRENT) {
-            if (Utils.unlockWorkProfileIfNecessary(getContext(), mUserId) ||
+            if (Utils.confirmWorkProfileCredentialsIfNecessary(getContext(), mUserId) ||
                     Utils.startQuietModeDialogIfNecessary(getContext(),
                             UserManager.get(getContext()), mUserId)) {
                 return;