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/redfish-core/lib/virtual_media.hpp b/redfish-core/lib/virtual_media.hpp
index f617f4a..9333f61 100644
--- a/redfish-core/lib/virtual_media.hpp
+++ b/redfish-core/lib/virtual_media.hpp
@@ -87,7 +87,7 @@
                 {
                     const std::string* imageUrlValue =
                         std::get_if<std::string>(&value);
-                    if (imageUrlValue && !imageUrlValue->empty())
+                    if (imageUrlValue != nullptr && !imageUrlValue->empty())
                     {
                         std::filesystem::path filePath = *imageUrlValue;
                         if (!filePath.has_filename())