[General] fixes fetch module credentials

[zhongwuzw]

Summary

In #14063, we decided to set withCredential to true by default, now if we use XMLHttpRequest, it works, but for fetch polyfill, withCredential is be set to false because we use Request's credentials https://github.com/facebook/react-native/blob/master/Libraries/vendor/core/whatwg-fetch.js#L515.

So we have inconsistency about withCrendential. My fix is to change Request credentials default value to same-origin, it reasonable because refer to MDN, the default value is same-origin.

cc. @cpojer.

Changelog

[General] [Fixed] - fixes fetch module credentials

Test Plan

For any request from either XMLHttpRequest or fetch, we set withCredential to true by default.

[zhigang1992]

Seems like this file is getting revert back to the npm version. #24418

[cpojer]

I don't think we can change this as we are getting rid of the fetch fork. Maybe we can change something in fetch to do the right thing by default for RN?

[zhongwuzw]

@cpojer Please see #24418 (comment) or #14063. We changed some behavior because react-native is not for web.