Move NetworkStackConstants to frameworks/libs/net

The class only contains constants that should be shareable between
different modules and tests.

Bug: 168868607
Test: m
Change-Id: Ic382d24e73697d85d29fa226692bd0d64ffa0f1f
diff --git a/staticlibs/Android.bp b/staticlibs/Android.bp
index e5cc8b1..252efb4 100644
--- a/staticlibs/Android.bp
+++ b/staticlibs/Android.bp
@@ -52,6 +52,9 @@
         "//packages/modules/CaptivePortalLogin",
         "//frameworks/libs/net/common/tests:__subpackages__",
   ],
+  static_libs: [
+        "net-utils-framework-common",
+  ],
   libs: [
       "androidx.annotation_annotation",
   ],