Add a CTS test for carrier config certificates

Bug: 141026377
Test: CTS
Change-Id: I733ea1b715e7e5fc082876bbd483760c9172dcdf
diff --git a/src/com/android/phone/CarrierConfigLoader.java b/src/com/android/phone/CarrierConfigLoader.java
index c5b4875..c5e913c 100644
--- a/src/com/android/phone/CarrierConfigLoader.java
+++ b/src/com/android/phone/CarrierConfigLoader.java
@@ -566,6 +566,13 @@
             configPackagename = mPlatformCarrierConfigPackage;
             configToSend = mConfigFromDefaultApp[phoneId];
         }
+
+        // mOverrideConfigs is for testing. And it will override current configs.
+        PersistableBundle config = mOverrideConfigs[phoneId];
+        if (config != null) {
+            configToSend.putAll(config);
+        }
+
         mSubscriptionInfoUpdater.updateSubscriptionByCarrierConfigAndNotifyComplete(
                 phoneId, configPackagename, configToSend,
                 mHandler.obtainMessage(EVENT_SUBSCRIPTION_INFO_UPDATED, phoneId, -1));