Add kotlin-reflect to net-tests-utils

This fixes failures in CtsNetTestCases, where
TestableNetworkCallback.TAG cannot be used because
it uses kotlin-reflect.

Change-Id: I7e76fe224b1098c967665275eac24fcac08fca23
Fixes: 176047509
Test: atest CtsNetTestCasesLatestSdk
diff --git a/staticlibs/Android.bp b/staticlibs/Android.bp
index 76aceda..80a3589 100644
--- a/staticlibs/Android.bp
+++ b/staticlibs/Android.bp
@@ -99,6 +99,7 @@
     ],
     static_libs: [
         "androidx.test.ext.junit",
+        "kotlin-reflect",
         "libnanohttpd",
         "net-tests-utils-host-device-common",
         "net-utils-device-common",