Add asset picker support to spawn SC node and thread safety measures

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Spawnable/ProcesedObjectStore.cpp

@@ -10,7 +10,7 @@
  *
  */
 
-#include <AzCore/Casting/lossy_cast.h>
+#include <AzFramework/Spawnable/SpawnableAssetHandler.h>
 #include <AzToolsFramework/Prefab/Spawnable/ProcesedObjectStore.h>
 
 namespace AzToolsFramework::Prefab::PrefabConversionUtils
@@ -73,8 +73,7 @@ namespace AzToolsFramework::Prefab::PrefabConversionUtils
 
     uint32_t ProcessedObjectStore::BuildSubId(AZStd::string_view id)
     {
-        AZ::Uuid subIdHash = AZ::Uuid::CreateData(id.data(), id.size());
-        return azlossy_caster(subIdHash.GetHash());
+        return AzFramework::SpawnableAssetHandler::BuildSubId(id);
     }
 
     const AZStd::string& ProcessedObjectStore::GetId() const