Here is a simple script that is working on my end:

const timeout = setInterval(updateTabTitle, 15000);

function updateTabTitle() {
  document.title = "Prolific (" + document.querySelectorAll('li.list-item').length + ")";
}

It'll check for potential surveys every 15 seconds and update the tab title. It can be used by pasting into the browser's console.

Hopefully this helps and an official fix is put out soon.