overrideConfig API did not notify platform correctly

In the case when overrideConfig was being passed null
to remove any overrides, it was not notifying the system
of the change.

Bug: 131614858
Test: atest GtsTelephonyTestCases
Merged-In: I0f9445dcc22d8383608191cf56630beb5c7b0726
Change-Id: I7e0342c5b2edb9c3f4b0547c424233a4f73733f2
diff --git a/src/com/android/phone/CarrierConfigLoader.java b/src/com/android/phone/CarrierConfigLoader.java
index 8299d86..da478fa 100644
--- a/src/com/android/phone/CarrierConfigLoader.java
+++ b/src/com/android/phone/CarrierConfigLoader.java
@@ -935,10 +935,7 @@
 
         if (overrides == null) {
             mOverrideConfigs[phoneId] = new PersistableBundle();
-            return;
-        }
-
-        if (mOverrideConfigs[phoneId] == null) {
+        } else if (mOverrideConfigs[phoneId] == null) {
             mOverrideConfigs[phoneId] = overrides;
         } else {
             mOverrideConfigs[phoneId].putAll(overrides);