[NS04.5] Have NetworkOffer embark a provider ID

...instead of a Messenger.
This will be useful later to compare whether a given offer is
offered by the same provider satisfying a request.

Bug: 167544279
Test: ConnectivityServiceTest
Change-Id: I975a9439021c7fa511c50ac982819b6dd146291e

framework/src/android/net/ConnectivityManager.java

@@ -3261,11 +3261,11 @@ public class ConnectivityManager {
     @RequiresPermission(anyOf = {
             NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
             android.Manifest.permission.NETWORK_FACTORY})
-    public void offerNetwork(@NonNull final NetworkProvider provider,
+    public void offerNetwork(@NonNull final int providerId,
             @NonNull final NetworkScore score, @NonNull final NetworkCapabilities caps,
             @NonNull final INetworkOfferCallback callback) {
         try {
-            mService.offerNetwork(Objects.requireNonNull(provider.getMessenger(), "null messenger"),
+            mService.offerNetwork(providerId,
                     Objects.requireNonNull(score, "null score"),
                     Objects.requireNonNull(caps, "null caps"),
                     Objects.requireNonNull(callback, "null callback"));