Hide WFC settings if WFC is not provisioned (and provisioning is required)

Bug: 29223318
Change-Id: I26044659cb8540654ec7dfa1f92fdd98a68f01b8
diff --git a/src/com/android/phone/CallFeaturesSetting.java b/src/com/android/phone/CallFeaturesSetting.java
index d74558f..33aba17 100644
--- a/src/com/android/phone/CallFeaturesSetting.java
+++ b/src/com/android/phone/CallFeaturesSetting.java
@@ -300,7 +300,8 @@
             } else {
                 prefSet.removePreference(wifiCallingSettings);
             }
-        } else if (!ImsManager.isWfcEnabledByPlatform(mPhone.getContext())) {
+        } else if (!ImsManager.isWfcEnabledByPlatform(mPhone.getContext()) ||
+                !ImsManager.isWfcProvisionedOnDevice(mPhone.getContext())) {
             prefSet.removePreference(wifiCallingSettings);
         } else {
             int resId = com.android.internal.R.string.wifi_calling_off_summary;