Fix "Turn on phone calls" for guest user

Move "Turn on phone calls" from guest detail user screen to user screen.
Optimisation: Applying restrictions to default guest user has been moved
to UserManagerService -> setDefaultGuestRestrictions.

Following UX there is no need for confirmation dialog.

Bug: 191483069
Test: make RunSettingsRoboTests -j128 ROBOTEST_FILTER="com.android.settings.users.GuestTelephonyPreferenceControllerTest"
       make RunSettingsRoboTests -j128 ROBOTEST_FILTER="com.android.settings.users.UserSettingsTest"
Change-Id: Id7391d3f85954ea7f9c94791f24174105ec8073e

src/com/android/settings/users/UserDialogs.java

@@ -145,21 +145,6 @@ public final class UserDialogs {
                 .create();
     }
 
-    /**
-     * Creates a dialog to confirm that the user is ok to enable phone calls (no SMS).
-     *
-     * @param onConfirmListener Callback object for positive action
-     */
-    public static Dialog createEnablePhoneCallsDialog(Context context,
-            DialogInterface.OnClickListener onConfirmListener) {
-        return new AlertDialog.Builder(context)
-                .setTitle(R.string.user_enable_calling_confirm_title)
-                .setMessage(R.string.user_enable_calling_confirm_message)
-                .setPositiveButton(R.string.okay, onConfirmListener)
-                .setNegativeButton(android.R.string.cancel, null)
-                .create();
-    }
-
     /**
      * Creates a dialog to confirm that the user is ok to start setting up a new user.
      *