Let the dashboard's sort dropdown span the shares card

The sort select above the admin dashboard's shares list was capped at
20rem by the admin-shares-sort wrapper. The wrapper and its rule in
app.css are gone, so the select stretches with the card's stack like
the other fields. CHANGELOG (Unreleased) notes it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

resources/css/app.css

@@ -289,15 +289,6 @@
     max-inline-size: 24rem;
 }
 
-/*
- * resources/views/livewire/admin/admin-dashboard.blade.php: the sort select above the shares list
- * keeps to the width its longest option needs instead of spanning the card. No `<x-select>` width
- * prop caps it, and 20rem matches no `<x-pane>` preset.
- */
-.admin-shares-sort {
-    max-inline-size: 20rem;
-}
-
 /*
  * resources/views/livewire/admin/admin-dashboard.blade.php: a share's details are two lines of
  * their own (its files, size and downloads; its expiry), and they wrap rather than clip. The