Use native HTTP requests

For historical reasons, some endpoints are not configured properly and throw a CORS error when requested through a browser (or a WebView, in native apps). Because of that, we are making native HTTP requests for certain situations where this happens.

One of the times when we're still using browser requests is the login, which should work for the most part. But we've seen sites misconfigured that throw CORS errors in any endpoint, and that's a common source of issues.

In order to minimize it, and given that we're already doing native requests in some situations, it'd be easier to just use native requests everywhere. We may still find the issues in iframes and such, but it won't be as disruptive as preventing logging in.