LibWeb: Cast unused smart-pointer return values to void

Author: https://github.com/AtkinsSJ
Commit: 7196570f9b
Pull-request: https://github.com/SerenityOS/serenity/pull/11151

Userland/Libraries/LibWeb/HTML/HTMLScriptElement.cpp

@@ -390,7 +390,7 @@ void HTMLScriptElement::prepare_script()
 
                 // 3. Remove the first element from this list of scripts that will execute in order
                 //    as soon as possible.
-                m_preparation_time_document->scripts_to_execute_as_soon_as_possible().take_first();
+                (void)m_preparation_time_document->scripts_to_execute_as_soon_as_possible().take_first();
 
                 // 4. If this list of scripts that will execute in order as soon as possible is still
                 //    not empty and the first entry has already been marked as ready, then jump back