Add announcements (#12662)

* Add announcements

Fix #11006

* Add reactions to announcements

* Add admin UI for announcements

* Add unit tests

* Fix issues

- Add `with_dismissed` param to announcements API
- Fix end date not being formatted when time range is given
- Fix announcement delete causing reactions to send streaming updates
- Fix announcements container growing too wide and mascot too small
- Fix `all_day` being settable when no time range is given
- Change text "Update" to "Announcement"

* Fix scheduler unpublishing announcements before they are due

* Fix filter params not being passed to announcements filter

app/javascript/mastodon/actions/notifications.js

@@ -157,9 +157,9 @@ export function expandNotifications({ maxId } = {}, done = noOp) {
 
       dispatch(expandNotificationsSuccess(response.data, next ? next.uri : null, isLoadingMore, isLoadingRecent, isLoadingRecent && preferPendingItems));
       fetchRelatedRelationships(dispatch, response.data);
-      done();
     }).catch(error => {
       dispatch(expandNotificationsFail(error, isLoadingMore));
+    }).finally(() => {
       done();
     });
   };
@@ -188,6 +188,7 @@ export function expandNotificationsFail(error, isLoadingMore) {
     type: NOTIFICATIONS_EXPAND_FAIL,
     error,
     skipLoading: !isLoadingMore,
+    skipAlert: !isLoadingMore,
   };
 };