fix: Remove all_special_tokens_extended for transformers v5 compatibility in OpenAI frontend (#8817)

Author: yinggeh

python/openai/openai_frontend/engine/utils/tokenizer.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2024-2025, NVIDIA CORPORATION. All rights reserved.
+# Copyright (c) 2024-2026, NVIDIA CORPORATION. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
@@ -47,7 +47,6 @@ def get_cached_tokenizer(
     function caches these properties for faster access."""
 
     tokenizer_all_special_ids = set(tokenizer.all_special_ids)
-    tokenizer_all_special_tokens_extended = tokenizer.all_special_tokens_extended
     tokenizer_all_special_tokens = set(tokenizer.all_special_tokens)
     tokenizer_len = len(tokenizer)
 
@@ -60,10 +59,6 @@ def all_special_ids(self):
         def all_special_tokens(self):
             return tokenizer_all_special_tokens
 
-        @property
-        def all_special_tokens_extended(self):
-            return tokenizer_all_special_tokens_extended
-
         def __len__(self):
             return tokenizer_len