fix: Pass HTTP Auth credentials along with JS "fetch" calls

As per #140 (closed), the default behavior of the Javascript internal method "fetch" does not currently properly pass along HTTP-Auth credentials added by the user. This MR seeks to address this issue by updating our "fetch" calls in this manner, such that they will work on password-protected environments like staging and our review-apps.

assigned to @stephen

i'm not sure exactly which part of !159 (comment 3084115) this is supposed to fix, but on https://use-http-auth-creds-with-fetch.donate-review.torproject.net/ i'm still getting "verification failed, try again later" and when i click on the "I'm not a robot" button, i still get the error:

Uncaught (in promise) TypeError: statesColl is null
    filterStates https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/modules/locations.min.js:1
    init https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/script.min.js:1
    jQuery 5
3 locations.min.js:1:1277
ALTCHA TypeError: Window.fetch: /challenge/ is an url with embedded credentials.
    jt https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
    K https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
    Tt https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
altcha.iife.js:1:18703
    R https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
    K https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
    (Async: promise callback)
    K https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
    Tt https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
ALTCHA TypeError: Window.fetch: /challenge/ is an url with embedded credentials.
    jt https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
    K https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
    Tt https://tor-www@use-http-auth-creds-with-fetch.donate-review.torproject.net/static/js/altcha.iife.js:1
altcha.iife.js:1:18703

requested review from @anarcat

resolved all threads

approved this merge request

mentioned in commit 569eb940

merged

mentioned in issue #140 (closed)