SubscriptionUtil checks that SubscriptionInfo is null before accessing.

Test: atest -c SubscriptionUtilTest
Bug: 178707680
Change-Id: I03938405929c3307460107671bbe695ee5e0f6e9

src/com/android/settings/network/SubscriptionUtil.java

@@ -338,6 +338,9 @@ public class SubscriptionUtil {
     @VisibleForTesting
     public static CharSequence getUniqueSubscriptionDisplayName(
             SubscriptionInfo info, Context context) {
+        if (info == null) {
+            return "";
+        }
         return getUniqueSubscriptionDisplayName(info.getSubscriptionId(), context);
     }