Enable readability-container-size-empty tests

This one is a little trivial, but it does help in readability.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I5366d4eec8af2f781b3bad804131ae2eb806e3aa
diff --git a/include/nbd_proxy.hpp b/include/nbd_proxy.hpp
index ed5265d..3f97f8c 100644
--- a/include/nbd_proxy.hpp
+++ b/include/nbd_proxy.hpp
@@ -193,7 +193,7 @@
             return;
         }
 
-        if (ws2uxBuf.size() == 0)
+        if (ws2uxBuf.empty())
         {
             BMCWEB_LOG_ERROR << "No data to write to UNIX socket";
             return;