Add test for downstream tethering

Add end-to-end testing for testing NsdManager advertising and
discovering works fine with downstream tethering interfaces.

Bug: 281639507
Test: atest NsdManagerTest
Change-Id: I5a66423f216cfe0c82db5128502c885980ab264b
diff --git a/tests/cts/net/Android.bp b/tests/cts/net/Android.bp
index 1276d59..6de663a 100644
--- a/tests/cts/net/Android.bp
+++ b/tests/cts/net/Android.bp
@@ -56,6 +56,7 @@
         "modules-utils-build",
         "net-utils-framework-common",
         "truth-prebuilt",
+        "TetheringIntegrationTestsBaseLib",
     ],
 
     // uncomment when b/13249961 is fixed