Remove jQuery AJAX from the archive download links (#29380)

- Removed all jQuery AJAX calls and replaced with our fetch wrapper
- Tested the repo archive download links dropdown functionality and it
works as before

# Demo using `fetch` instead of jQuery AJAX

![action](https://github.com/go-gitea/gitea/assets/20454870/db791249-bca1-4d22-ac5e-623f68023e15)

---------

Signed-off-by: Yarden Shoham <git@yardenshoham.com>

web_src/js/features/repo-common.js

@@ -1,38 +1,34 @@
 import $ from 'jquery';
 import {hideElem, showElem} from '../utils/dom.js';
+import {POST} from '../modules/fetch.js';
 
-const {csrfToken} = window.config;
-
-function getArchive($target, url, first) {
-  $.ajax({
-    url,
-    type: 'POST',
-    data: {
-      _csrf: csrfToken,
-    },
-    complete(xhr) {
-      if (xhr.status === 200) {
-        if (!xhr.responseJSON) {
-          // XXX Shouldn't happen?
-          $target.closest('.dropdown').children('i').removeClass('loading');
-          return;
-        }
+async function getArchive($target, url, first) {
+  try {
+    const response = await POST(url);
+    if (response.status === 200) {
+      const data = await response.json();
+      if (!data) {
+        // XXX Shouldn't happen?
+        $target.closest('.dropdown').children('i').removeClass('loading');
+        return;
+      }
 
-        if (!xhr.responseJSON.complete) {
-          $target.closest('.dropdown').children('i').addClass('loading');
-          // Wait for only three quarters of a second initially, in case it's
-          // quickly archived.
-          setTimeout(() => {
-            getArchive($target, url, false);
-          }, first ? 750 : 2000);
-        } else {
-          // We don't need to continue checking.
-          $target.closest('.dropdown').children('i').removeClass('loading');
-          window.location.href = url;
-        }
+      if (!data.complete) {
+        $target.closest('.dropdown').children('i').addClass('loading');
+        // Wait for only three quarters of a second initially, in case it's
+        // quickly archived.
+        setTimeout(() => {
+          getArchive($target, url, false);
+        }, first ? 750 : 2000);
+      } else {
+        // We don't need to continue checking.
+        $target.closest('.dropdown').children('i').removeClass('loading');
+        window.location.href = url;
       }
-    },
-  });
+    }
+  } catch {
+    $target.closest('.dropdown').children('i').removeClass('loading');
+  }
 }
 
 export function initRepoArchiveLinks() {