fix: 修复 alist 一些问题

Author: tianxiu2b2t

core/storages/__init__.py

@@ -240,6 +240,7 @@ async def _action_data(self, action: str, url: str, data: Any, headers: dict[str
                     )
                     if result.code != 200:
                         logger.terror("storage.error.alist", status=result.code, message=result.message)
+                        logger.debug(result)
                     else:
                         self.cache.set(hash, result, 30)
                     return result
@@ -330,7 +331,7 @@ def empty():
                             logger.terror("storage.error.alist", status=result.code, message=result.message)
                         else:
                             self.cache.set(f"listfile_{root}", result, 30)
-                for r in result.data["content"]:
+                for r in result.data["content"] or []:
                     file = File(
                         r["name"],
                         r["size"],