Add unit test for shared/unshared interface quotas

Test: as follows
    - built
    - flashed
    - booted
    - "runtest -x .../netd_unit_test.cpp" passes
Bug: 28362720
Bug: 38143143

Change-Id: I0b962898f9e3d7e86d5c0d0d01b79b3e3543b5ee
diff --git a/libnetdutils/include/netdutils/StatusOr.h b/libnetdutils/include/netdutils/StatusOr.h
index 6afbfcb..d68cced 100644
--- a/libnetdutils/include/netdutils/StatusOr.h
+++ b/libnetdutils/include/netdutils/StatusOr.h
@@ -65,11 +65,7 @@
 
 template <typename T>
 inline std::ostream& operator<<(std::ostream& os, const StatusOr<T>& s) {
-    os << "StatusOr[status: " << s.status();
-    if (isOk(s)) {
-        os << ", value: " << s.value();
-    }
-    return os << "]";
+    return os << "StatusOr[status: " << s.status() << "]";
 }
 
 #define ASSIGN_OR_RETURN_IMPL(tmp, lhs, stmt) \