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.

web_src/js/features/comp/ReactionSelector.js

@@ -1,6 +1,5 @@
 import $ from 'jquery';
-
-const {csrfToken} = window.config;
+import {POST} from '../../modules/fetch.js';
 
 export function initCompReactionSelector($parent) {
   $parent.find(`.select-reaction .item.reaction, .comment-reaction-button`).on('click', async function (e) {
@@ -12,15 +11,8 @@ export function initCompReactionSelector($parent) {
     const reactionContent = $(this).attr('data-reaction-content');
     const hasReacted = $(this).closest('.ui.segment.reactions').find(`a[data-reaction-content="${reactionContent}"]`).attr('data-has-reacted') === 'true';
 
-    const res = await fetch(`${actionUrl}/${hasReacted ? 'unreact' : 'react'}`, {
-      method: 'POST',
-      headers: {
-        'content-type': 'application/x-www-form-urlencoded',
-      },
-      body: new URLSearchParams({
-        _csrf: csrfToken,
-        content: reactionContent,
-      }),
+    const res = await POST(`${actionUrl}/${hasReacted ? 'unreact' : 'react'}`, {
+      data: new URLSearchParams({content: reactionContent}),
     });
 
     const data = await res.json();