Use fetch helpers instead of fetch (#27026)

WIP because:

- [x] Some calls set a `content-type` but send no body, can likely
remove the header
- [x] Need to check whether `charset=utf-8` has any significance on the
webauthn calls, I assume not as it is the default for json content.
- [x] Maybe `no-restricted-globals` is better for eslint, but will
require a lot of duplication in the yaml or moving eslint config to a
`.js` extension.
- [x] Maybe export `request` as `fetch`, shadowing the global.

docs/content/contributing/guidelines-frontend.en-us.md

@@ -95,7 +95,7 @@ Some lint rules and IDEs also have warnings if the returned Promise is not handl
 ### Fetching data
 
 To fetch data, use the wrapper functions `GET`, `POST` etc. from `modules/fetch.js`. They
-accept a `data` option for the content, will automatically set CSFR token and return a
+accept a `data` option for the content, will automatically set CSRF token and return a
 Promise for a [Response](https://developer.mozilla.org/en-US/docs/Web/API/Response).
 
 ### HTML Attributes and `dataset`