[CI Failure] fix models/language/pooling/test_auto_prefix_cache_support.py (#24636)

Signed-off-by: wang.yuqi <noooop@126.com>

vllm/config/__init__.py

@@ -3558,6 +3558,10 @@ class VllmConfig:
                     disable_chunked_prefill_reasons.append(
                         "Only \"last\" pooling supports chunked "
                         "prefill and prefix caching; disabling both.")
+                if not getattr(self.model_config.hf_config, "is_causal", True):
+                    disable_chunked_prefill_reasons.append(
+                        "Only models using causal attention supports chunked "
+                        "prefill and prefix caching; disabling both.")
             elif self.model_config.is_encoder_decoder:
                 self.scheduler_config.max_num_encoder_input_tokens = \
                     MULTIMODAL_REGISTRY.get_encdec_max_encoder_len(self.model_config)