fix(xsfetch): make retry work, remove the exposure of retryCount

[junkwarrior87]

Hi, I've found an issue in xsfetch that retry does not take effect.
Essentially it's options.retry < options.retryCount needs to be options.retry > options.retryCount.

It can be easily reproduced by the following code (you might add some debug logs in the retry logic to see that it is not executed):

import { createFetch } from 'xsfetch';

const fetch = createFetch({
  retry: 3,
  retryDelay: 1000,
  retryStatusCodes: [404],
});

fetch('https://jsonplaceholder.typicode.com/todos/500')
  .then(console.log, console.error);

This PR is fixing the issue and also performing a little bit refactoring that eliminates the need for exposing retryCount in the fetch options.

[kwaa]

Thanks for the contribution! I'll merge after fixing the lint error.