Fix various loading states, remove `.loading` class (#29920)

Various code was using fomantic `loading` class which I think got broken
a while ago and rendered only a full circle. Fix those to use
`is-loading`.

Before:
<img width="295" alt="Screenshot 2024-03-19 at 22 56 26"
src="https://github.com/go-gitea/gitea/assets/115237/dbe83395-5db4-4868-90bc-3613866a35f0">

After:
<img width="60" alt="Screenshot 2024-03-19 at 22 54 35"
src="https://github.com/go-gitea/gitea/assets/115237/8ac19b7e-035a-4c6d-850b-53a234ef69c2">
<img width="294" alt="Screenshot 2024-03-19 at 22 54 56"
src="https://github.com/go-gitea/gitea/assets/115237/34e819d7-25f7-43a1-9d48-4a68dcd2b6ad">
<img width="320" alt="Screenshot 2024-03-19 at 22 55 16"
src="https://github.com/go-gitea/gitea/assets/115237/05127544-47ff-4e18-9fd8-c84e44c374f8">
<img width="153" alt="Screenshot 2024-03-19 at 23 01 43"
src="https://github.com/go-gitea/gitea/assets/115237/a33248c6-b11d-40ff-82d8-f5a3d85b55aa">
<img width="1300" alt="Screenshot 2024-03-19 at 23 56 25"
src="https://github.com/go-gitea/gitea/assets/115237/562ca876-b5d5-4295-961e-9d2cdab31ab0">
<img width="136" alt="Screenshot 2024-03-20 at 00 00 38"
src="https://github.com/go-gitea/gitea/assets/115237/44838ac4-67f3-4fec-a8e3-978cc5dbdb72">

4 files changed, 13 insertions, 11 deletions

diff --git a/web_src/js/features/admin/common.js b/web_src/js/features/admin/common.js
index 31d840c3e1..0c65f04ab8 100644
--- a/web_src/js/features/admin/common.js
+++ b/web_src/js/features/admin/common.js
@@ -208,7 +208,7 @@ export function initAdminCommon() {
     $('#delete-selection').on('click', async function (e) {
       e.preventDefault();
       const $this = $(this);
-      $this.addClass('loading disabled');
+      $this.addClass('is-loading disabled');
       const data = new FormData();
       $checkboxes.each(function () {
         if ($(this).checkbox('is checked')) {
diff --git a/web_src/js/features/comp/WebHookEditor.js b/web_src/js/features/comp/WebHookEditor.js
index b7ca5a0fcf..d74b59fd2a 100644
--- a/web_src/js/features/comp/WebHookEditor.js
+++ b/web_src/js/features/comp/WebHookEditor.js
@@ -35,7 +35,7 @@ export function initCompWebHookEditor() {
 
   // Test delivery
   document.getElementById('test-delivery')?.addEventListener('click', async function () {
-    this.classList.add('loading', 'disabled');
+    this.classList.add('is-loading', 'disabled');
     await POST(this.getAttribute('data-link'));
     setTimeout(() => {
       window.location.href = this.getAttribute('data-redirect');
diff --git a/web_src/js/features/repo-common.js b/web_src/js/features/repo-common.js
index 669b47a9c5..2c5746c738 100644
--- a/web_src/js/features/repo-common.js
+++ b/web_src/js/features/repo-common.js
@@ -3,18 +3,20 @@ import {hideElem, showElem} from '../utils/dom.js';
 import {POST} from '../modules/fetch.js';
 
 async function getArchive($target, url, first) {
+  const dropdownBtn = $target[0].closest('.ui.dropdown.button');
+
   try {
+    dropdownBtn.classList.add('is-loading');
     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');
+        dropdownBtn.classList.remove('is-loading');
         return;
       }
 
       if (!data.complete) {
-        $target.closest('.dropdown').children('i').addClass('loading');
         // Wait for only three quarters of a second initially, in case it's
         // quickly archived.
         setTimeout(() => {
@@ -22,12 +24,12 @@ async function getArchive($target, url, first) {
         }, first ? 750 : 2000);
       } else {
         // We don't need to continue checking.
-        $target.closest('.dropdown').children('i').removeClass('loading');
+        dropdownBtn.classList.remove('is-loading');
         window.location.href = url;
       }
     }
   } catch {
-    $target.closest('.dropdown').children('i').removeClass('loading');
+    dropdownBtn.classList.remove('is-loading');
   }
 }
 
diff --git a/web_src/js/features/repo-issue.js b/web_src/js/features/repo-issue.js
index ad2956a600..c91dd06ac9 100644
--- a/web_src/js/features/repo-issue.js
+++ b/web_src/js/features/repo-issue.js
@@ -43,14 +43,14 @@ export function initRepoIssueTimeTracking() {
 
 async function updateDeadline(deadlineString) {
   hideElem($('#deadline-err-invalid-date'));
-  $('#deadline-loader').addClass('loading');
+  $('#deadline-loader').addClass('is-loading');
 
   let realDeadline = null;
   if (deadlineString !== '') {
     const newDate = Date.parse(deadlineString);
 
     if (Number.isNaN(newDate)) {
-      $('#deadline-loader').removeClass('loading');
+      $('#deadline-loader').removeClass('is-loading');
       showElem($('#deadline-err-invalid-date'));
       return false;
     }
@@ -69,7 +69,7 @@ async function updateDeadline(deadlineString) {
     }
   } catch (error) {
     console.error(error);
-    $('#deadline-loader').removeClass('loading');
+    $('#deadline-loader').removeClass('is-loading');
     showElem($('#deadline-err-invalid-date'));
   }
 }
@@ -237,14 +237,14 @@ export function initRepoPullRequestUpdate() {
     e.preventDefault();
     const $this = $(this);
     const redirect = $this.data('redirect');
-    $this.addClass('loading');
+    $this.addClass('is-loading');
     let response;
     try {
       response = await POST($this.data('do'));
     } catch (error) {
       console.error(error);
     } finally {
-      $this.removeClass('loading');
+      $this.removeClass('is-loading');
     }
     let data;
     try {