Fix new essentials asset library not being covered in library path query

source/blender/asset_system/intern/asset_library_service.cc

@@ -215,6 +215,10 @@ std::string AssetLibraryService::root_path_from_library_ref(
     return "";
   }
 
+  if (ELEM(library_reference.type, ASSET_LIBRARY_ESSENTIALS)) {
+    return essentials_directory_path();
+  }
+
   bUserAssetLibrary *custom_library = find_custom_asset_library_from_library_ref(
       library_reference);
   if (!custom_library || !custom_library->path[0]) {