Adding '.network.spawnable' as a network constant

Signed-off-by: Gene Walters <genewalt@amazon.com>

Gems/Multiplayer/Code/Source/NetworkEntity/NetworkSpawnableLibrary.cpp

@@ -11,6 +11,7 @@
 #include <AzCore/Component/ComponentApplicationLifecycle.h>
 #include <AzFramework/Spawnable/Spawnable.h>
 #include <AzCore/Interface/Interface.h>
+#include <Multiplayer/MultiplayerConstants.h>
 
 namespace Multiplayer
 {
@@ -42,7 +43,7 @@ namespace Multiplayer
         auto enumerateCallback = [this](const AZ::Data::AssetId id, const AZ::Data::AssetInfo& info)
         {
             if (info.m_assetType == AZ::AzTypeInfo<AzFramework::Spawnable>::Uuid() &&
-                info.m_relativePath.ends_with(".network.spawnable"))
+                info.m_relativePath.ends_with(NetworkSpawnableFileExtension))
             {
                 ProcessSpawnableAsset(info.m_relativePath, id);
             }