DO NOT MERGE ANYWHERE: WiFiCallingSettings: hide wfc mode preference if not editable

Bug: 30947921
Change-Id: I80240fbd912afa9a40cee38070c4e77d5e9d6ae9
(cherry picked from commit 4436d6fe16)

src/com/android/settings/WifiCallingSettings.java

@@ -363,7 +363,12 @@ public class WifiCallingSettings extends SettingsPreferenceFragment
         final PreferenceScreen preferenceScreen = getPreferenceScreen();
         boolean updateAddressEnabled = (getCarrierActivityIntent(context) != null);
         if (wfcEnabled) {
+            if (mEditableWfcMode) {
                 preferenceScreen.addPreference(mButtonWfcMode);
+            } else {
+                // Don't show WFC mode preference if it's not editable.
+                preferenceScreen.removePreference(mButtonWfcMode);
+            }
             if (updateAddressEnabled) {
                 preferenceScreen.addPreference(mUpdateAddress);
             } else {