Fixed several release build compile errors.

Code/Framework/AzFramework/AzFramework/Scene/Scene.inl

@@ -51,7 +51,7 @@ namespace AzFramework
     }
 
     template<typename T>
-    bool Scene::UnsetSubsystem(const T& system)
+    bool Scene::UnsetSubsystem([[maybe_unused]] const T& system)
     {
         const AZ::TypeId& targetType = azrtti_typeid<T>();
         const size_t systemKeysCount = m_systemKeys.size();

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponent.cpp

@@ -770,8 +770,8 @@ namespace AzToolsFramework
                 return false;
             }
 
-            Template& sourceTemplate = sourceTemplateReference->get();
 #if defined(AZ_ENABLE_TRACING)
+            Template& sourceTemplate = sourceTemplateReference->get();
             Template& targetTemplate = targetTemplateReference->get();
 #endif