properly handle wrong and default sort arg in dash table list

app/Http/Controllers/DashController.php

@@ -20,7 +20,9 @@ class DashController extends Controller
             return back();
         }
 
-        $data['tableSort'] = $sort = \Input::get('tableSort', 'last-updated');
+        $defaultSort = 'last-updated';
+
+        $sort = \Input::get('tableSort', $defaultSort);
 
         $data['sortOptions'] = [
             'most-visited' => 'Most Visited',
@@ -34,6 +36,12 @@ class DashController extends Controller
             'least-rows' => 'Shortest',
         ];
 
+        if (!in_array($sort, array_keys($data['sortOptions']))) {
+            $sort = $defaultSort;
+        }
+
+        $data['tableSort'] = $sort;
+
         $data['users'] = User::orderBy('updated_at', 'desc')
             ->withCount(['tables'])
             ->paginate(10, ['id', 'title', 'name', 'tables_count'], 'userPage')