ByteStreamCnvSvcLegacy: Fix cppcheck warning.

ByteStreamCnvSvcLegacy: Fix cppcheck warning.

Pass object by const reference, not by value.

Event/ByteStreamCnvSvcLegacy/ByteStreamCnvSvcLegacy/offline_EventStorage/v5_EventStorageRecords.h

 /*
-  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
 
 /**
@@ -178,7 +178,7 @@ namespace offline_EventStorage_v5 {
   };
 
   std::string string_record(void *ri, const void *pi);
-  std::string string_record(file_name_strings nst);
+  std::string string_record(const file_name_strings& nst);
   void reset_record(void *ri, const void *pi);
 
 } // for namespace

Event/ByteStreamCnvSvcLegacy/src/offline_EventStorage/v5_EventStorageRecords.cxx

 /*
-  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
 
 //
@@ -30,7 +30,7 @@ std::string offline_EventStorage_v5::string_record(void *ri, const void *pi) {
   return rs;	    
 }
 
-std::string offline_EventStorage_v5::string_record(offline_EventStorage_v5::file_name_strings nst) {
+std::string offline_EventStorage_v5::string_record(const offline_EventStorage_v5::file_name_strings& nst) {
   
   std::ostringstream s;