Fix list not being automatically unpinned when it returns 404 in web UI (#11045)

app/javascript/mastodon/actions/alerts.js

@@ -8,6 +8,7 @@ const messages = defineMessages({
 export const ALERT_SHOW    = 'ALERT_SHOW';
 export const ALERT_DISMISS = 'ALERT_DISMISS';
 export const ALERT_CLEAR   = 'ALERT_CLEAR';
+export const ALERT_NOOP    = 'ALERT_NOOP';
 
 export function dismissAlert(alert) {
   return {
@@ -36,7 +37,7 @@ export function showAlertForError(error) {
 
     if (status === 404 || status === 410) {
       // Skip these errors as they are reflected in the UI
-      return {};
+      return { type: ALERT_NOOP };
     }
 
     let message = statusText;

app/javascript/styles/mastodon/components.scss

@@ -3075,6 +3075,10 @@ a.status-card.compact:hover {
   display: flex;
 }
 
+.column-header__links {
+  margin-bottom: 14px;
+}
+
 .column-header__links .text-btn {
   margin-right: 10px;
 }