[CHORE]: x: T = None to x: Optional[T] = None (#24217)

api/core/model_runtime/model_providers/__base/tokenizers/gpt2_tokenizer.py

@@ -1,10 +1,10 @@
 import logging
 from threading import Lock
-from typing import Any
+from typing import Any, Optional
 
 logger = logging.getLogger(__name__)
 
-_tokenizer: Any = None
+_tokenizer: Optional[Any] = None
 _lock = Lock()