Clarify the purpose of the default asset library URLs in the editor

`localhost` was removed as it won't work out of the box. It can be added
by the user if they're working on the asset library itself.

This won't affect existing installations due to how the editor settings
are stored, but existing installations will keep working fine.

(cherry picked from commit eac8ba6ce8bf9ad2f8a0f2026718e784e3d32f54)

editor/plugins/asset_library_editor_plugin.cpp

@@ -612,8 +612,7 @@ void EditorAssetLibrary::_notification(int p_what) {
 
 void EditorAssetLibrary::_update_repository_options() {
 	Dictionary default_urls;
-	default_urls["godotengine.org"] = "https://godotengine.org/asset-library/api";
-	default_urls["localhost"] = "http://127.0.0.1/asset-library/api";
+	default_urls["godotengine.org (Official)"] = "https://godotengine.org/asset-library/api";
 	Dictionary available_urls = _EDITOR_DEF("asset_library/available_urls", default_urls, true);
 	repository->clear();
 	Array keys = available_urls.keys();