Add MdnsProber

MdnsProber is an implementation of MdnsPacketRepeater that will be used
to send probes for service names before advertising them, to know if
they are already in use.

Bug: 241738458
Test: atest
Change-Id: I4e5f779b891e2c665ba7f752fb5fbd4255070725
diff --git a/tests/unit/Android.bp b/tests/unit/Android.bp
index 8ed735a..209430a 100644
--- a/tests/unit/Android.bp
+++ b/tests/unit/Android.bp
@@ -74,6 +74,7 @@
         "java/com/android/server/connectivity/VpnTest.java",
         "java/com/android/server/net/ipmemorystore/*.java",
         "java/com/android/server/connectivity/mdns/**/*.java",
+        "java/com/android/server/connectivity/mdns/**/*.kt",
     ]
 }