Update handling of closure/callback task identification

@see laravel/framework#34999

The return string was changed from Closure to Callback in order to support PHP 8, which in turn broke how we were identifying closure tasks.

src/TaskIdentifier.php

@@ -27,7 +27,7 @@ public function __invoke($task)
                 return static::TYPE_CLOSURE;
             }
 
-            if (Str::is($task->getSummaryForDisplay(), 'Closure')) {
+            if (in_array($task->getSummaryForDisplay(), ['Callback', 'Closure'])) {
                 return static::TYPE_CLOSURE;
             }
         }