[Perf] Improved perf for resolve_chat_template_content_format (#20065)

Signed-off-by: Ilya Lavrenov <ilya.lavrenov@cerebras.net>
Signed-off-by: Will Eaton <weaton@redhat.com>

Author: ilyal-cerebras

vllm/entrypoints/chat_utils.py

@@ -293,6 +293,7 @@ def _try_extract_ast(chat_template: str) -> Optional[jinja2.nodes.Template]:
         return None
 
 
+@lru_cache(maxsize=32)
 def _detect_content_format(
     chat_template: str,
     *,