[Frontend] Use new Renderer for Completions and Tokenize API (#32863)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

vllm/transformers_utils/config.py

@@ -834,7 +834,7 @@ def parse_pooling_type(pooling_name: str):
 @cache
 def get_sentence_transformer_tokenizer_config(
     model: str | Path, revision: str | None = "main"
-):
+) -> dict[str, Any] | None:
     """
     Returns the tokenization configuration dictionary for a
     given Sentence Transformer BERT model.