fix guided decoding

Signed-off-by: MengqingCao <cmq0113@163.com>

Author: MengqingCao

vllm_ascend/worker/model_runner_v1.py

@@ -2000,7 +2000,7 @@ def execute_model(
                 logits = model_output_broadcast_data["logits"]
 
             # Apply structured output bitmasks if present
-            if scheduler_output.grammar_bitmask is not None:
+            if scheduler_output.structured_output_request_ids:
                 logits = self.apply_grammar_bitmask(scheduler_output, logits)
 
             # Sample the next token and get logprobs if needed.