Move CaptivePortalProbeResult to its own file

This is necessary to resolve visibility issues for the next change.

Bug: b/79499239
Test: runtest frameworks-net
Change-Id: I50bc96afe6ae88c8f58a693f0a4e821f1f9b3299
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index 5b73bba..7eef2d5 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -112,6 +112,7 @@
 import android.net.RouteInfo;
 import android.net.StringNetworkSpecifier;
 import android.net.UidRange;
+import android.net.captiveportal.CaptivePortalProbeResult;
 import android.net.metrics.IpConnectivityLog;
 import android.net.util.MultinetworkPolicyTracker;
 import android.os.ConditionVariable;