fix AttributeError when result.info is not a dict

result.info returns the task's return value (e.g. an int) when the
Celery task completes before apply_async checks it. Use isinstance
check instead of truthiness to avoid calling .get() on non-dict values.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: snopoke

taskbadger/celery.py

@@ -131,7 +131,7 @@ def apply_async(self, *args, **kwargs):
 
         result = super().apply_async(*args, **kwargs)
 
-        tb_task_id = result.info.get(TB_TASK_ID) if result.info else None
+        tb_task_id = result.info.get(TB_TASK_ID) if isinstance(result.info, dict) else None
         setattr(result, TB_TASK_ID, tb_task_id)
 
         _get_task = functools.partial(get_task, tb_task_id) if tb_task_id else lambda: None