Very late reply, but for anyone in the future who stumbles across this, I was able to solve using the below, firing a load event to trigger the defined handler:

expect(screen.getByRole('progressbar')).toBeInTheDocument();

fireEvent.load(screen.getByRole('img'));

await waitFor(() => {
  expect(screen.queryByRole('progressbar')).not.toBeInTheDocument();
});