Fix presence.update event in the example

[allburov]

There was a typo in presence.update

[whiskeysockets-bot]

Thanks for your contribution.

The next step is to wait for review and approval to merge it to main repository

The community can help reacting with a thumb up (:thumbsup:) for approval and rocket (:rocket:) for who has tested it.

To test this PR you can run the following command below:

# NPM
npm install @whiskeysockets/baileys@allburov/Baileys#patch-1
# YARN v2
yarn add @whiskeysockets/baileys@allburov/Baileys#patch-1