Fix popping up the the VoLTE screen when it's disabled by the carrier.

- If only has the default carrier config just return, to
  avoid popping up the the VoLTE screen when it's disabled
  by the carrier.

Bug: 332647055
Test: manual
Flag: NONE bugfix
Change-Id: I71bc02f5044535d48726a531e36d57df73bc0f5f

src/com/android/settings/network/telephony/Enhanced4gBasePreferenceController.java

@@ -107,8 +107,8 @@ public class Enhanced4gBasePreferenceController extends TelephonyTogglePreferenc
         }
 
         final PersistableBundle carrierConfig = getCarrierConfigForSubId(subId);
-        if ((carrierConfig == null)
-                || carrierConfig.getBoolean(CarrierConfigManager.KEY_HIDE_ENHANCED_4G_LTE_BOOL)) {
+        if (!CarrierConfigManager.isConfigForIdentifiedCarrier(carrierConfig) ||
+                carrierConfig.getBoolean(CarrierConfigManager.KEY_HIDE_ENHANCED_4G_LTE_BOOL)) {
             return CONDITIONALLY_UNAVAILABLE;
         }