async unpin() {
        return await this.client.pupPage.evaluate(async (msgId) => {
            return await window.WWebJS.pinUnpinMsgAction(msgId, 2);
        }, this.id._serialized);
    }
Unpins the message (group admins can unpin messages of all group members)
@returns {Promise<boolean>} Returns true if the operation completed successfully, false otherwise