There is a workaround. You can create a script to automatically close these. However, if something urgent happened and they made a pop up for it, you won't see it.

Every alert has it's own id, so it's possible to hide just the Telegram message without subsequently hiding any future messages in the process. To do so, you'll need a way to inject css on page load. I suggest to use Stylus, which is available for both Chrome, Firefox and Opera.

After you installed Stylus, simply make sure you are on Codeforces, press it's action button and click on the "codeforces" part underneath "Write style for" (so that the hover text says domain("codeforces.com")):

This will open an Edit Style tab, in which you can paste the following code:

.alert[data-infobarid="25"] {
    display: none;
}

Press Ctrl + S to save and the message will be gone.

MikeMirzayanov Please remove and make page with links to social networks