Add Log.wtf when transports are missing

Because onCapabilitiesChanged will always be called, transports should
always exist in the map. If the transports are missing, error should be
report through Log.wtf.

Bug: 282587998
Test: atest MdnsSocketProviderTest
Change-Id: Ie2a93217542bfa6ee30bf3b9f73eb4ae8473fd09
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java
index ca61d34..3a3e53d 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java
@@ -414,8 +414,10 @@
             if (networkKey == LOCAL_NET) {
                 transports = new int[0];
             } else {
-                transports = mActiveNetworksTransports.getOrDefault(
-                        ((NetworkAsKey) networkKey).mNetwork, new int[0]);
+                transports = mActiveNetworksTransports.get(((NetworkAsKey) networkKey).mNetwork);
+                if (transports == null) {
+                    Log.wtf(TAG, "transports is missing for key: " + networkKey);
+                }
             }
             if (networkInterface == null || !isMdnsCapableInterface(networkInterface, transports)) {
                 return;