function saveConfig(assistantConfigObject = null) {
  fs.writeFile(
    configFilePath,
    JSON.stringify(!assistantConfigObject ? assistantConfig : assistantConfigObject),
    () => {
      console.log(...consoleMessage('Updated Config'));
      displayQuickMessage(
        `${supportedLanguages[assistantConfig['language']].settingsUpdatedText}`,
      );
    },
  );
}
Saves the `config` in the 'User Data' to retrieve
it the next time Assistant is launched.

@param {*} assistantConfigObject
Pass config as an object or pass `null` to consider `assistantConfig`