message: fix unhandle promise rejection in getConfiguration
diff: @@ -36,7 +36,11 @@ export const ConfigurationFeature: Feature<_RemoteWorkspace, Configuration> = (B
  items: Array.isArray(arg) ? arg : [arg]
  };
  return this.connection.sendRequest(ConfigurationRequest.type, params).then((result) => {
  + if (Array.isArray(result)) {
  return Array.isArray(arg) ? result : result[0];
  + } else {
  + return Array.isArray(arg) ? [] : null;
  + }
  });
  }
  };
  