Minor fix for Web no threads

Source/Engine/Content/Storage/FlaxChunk.h

@@ -91,6 +91,7 @@ public:
     /// Flag set to indicate that chunk is during loading (atomic access to sync multiple reading threads).
     /// </summary>
     int64 IsLoading = 0;
+
     /// <summary>
     /// The chunk data.
     /// </summary>

Source/Engine/Content/Storage/FlaxStorage.cpp

@@ -714,10 +714,12 @@ bool FlaxStorage::LoadAssetChunk(FlaxChunk* chunk)
     ASSERT(IsLoaded());
     ASSERT(chunk != nullptr && _chunks.Contains(chunk));
 
+#if PLATFORM_THREADS_LIMIT > 1
     // Protect against loading the same chunk from multiple threads at once
     while (Platform::InterlockedCompareExchange(&chunk->IsLoading, 1, 0) != 0)
         Platform::Sleep(1);
     SCOPE_EXIT{ Platform::AtomicStore(&chunk->IsLoading, 0); };
+#endif
     if (chunk->IsLoaded())
         return false;