function stopPolling(userId) {
  logger.debug(`Stop polling Nextcloud Talk for user: ${userId}`);
  this.bots[userId].isPolling = false;
  this.bots[userId].lastKnownMessageId = null;
  this.bots[userId].eventEmitter.removeListener('message', this.newMessageCb);
}
@description Initiate bot poll message.
@param {string} userId - User to send message to.
@example
stopPoll('user1');