IMS: Make wifi call settings UI non indexable

- Visibility of wifi calling settings option is controlled
with operator mcc/mnc values.
- Make wifi calling settings UI non indexable when UI option
is removed.

Bug: 23895298
Change-Id: Ie5bdbdde5d17582eceeee07c2d5ee9fb361e00bc

src/com/android/settings/WirelessSettings.java

@@ -457,6 +457,10 @@ public class WirelessSettings extends SettingsPreferenceFragment implements Inde
                     result.add(KEY_TETHER_SETTINGS);
                 }
 
+                if (!ImsManager.isWfcEnabledByPlatform(context)) {
+                    result.add(KEY_WFC_SETTINGS);
+                }
+
                 return result;
             }
         };