Fix incorrect use of old WebUI paths (#16773)

* Fix incorrect use of old WebUI paths

PR #16171 renamed some routes but missed some occurrences.
Without #16772, this leads to unreachable routes in those cases.

* Fix floating action button being displayed on statuses and compose screen

app/javascript/mastodon/features/direct_timeline/components/conversation.js

@@ -81,7 +81,7 @@ class Conversation extends ImmutablePureComponent {
       markRead();
     }
 
-    this.context.router.history.push(`/statuses/${lastStatus.get('id')}`);
+    this.context.router.history.push(`/@${lastStatus.getIn(['account', 'acct'])}/${lastStatus.get('id')}`);
   }
 
   handleMarkAsRead = () => {