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/dbus_monitor.hpp b/include/dbus_monitor.hpp
index c8e46b7..9bc79ad 100644
--- a/include/dbus_monitor.hpp
+++ b/include/dbus_monitor.hpp
@@ -200,7 +200,7 @@
                      "member='PropertiesChanged'");
                 // If interfaces weren't specified, add a single match for all
                 // interfaces
-                if (thisSession.interfaces.size() == 0)
+                if (thisSession.interfaces.empty())
                 {
                     BMCWEB_LOG_DEBUG << "Creating match "
                                      << propertiesMatchString;