fb-message-remove.js

setInterval(() => removeFbMessage(), 3000);
function sleep() {
    return new Promise((resolve) => setTimeout(resolve, 1000));
}
const removeFbMessage = async () => {
    document.querySelector('[aria-label="More"]').click();
    await sleep();
    document.querySelector('[aria-label="Remove message"]').click();
    await sleep();
    document.querySelector('[aria-label="Remove"]').click();
};