Support Cross encoder models (#10400)

Signed-off-by: Max de Bayser <maxdebayser@gmail.com>
Signed-off-by: Max de Bayser <mbayser@br.ibm.com>
Signed-off-by: Flavia Beo <flavia.beo@ibm.com>
Co-authored-by: Flavia Beo <flavia.beo@ibm.com>

vllm/config.py

@@ -712,6 +712,11 @@ class ModelConfig:
     def is_multimodal_model(self) -> bool:
         return self.multimodal_config is not None
 
+    @property
+    def is_cross_encoder(self) -> bool:
+        architectures = getattr(self.hf_config, "architectures", [])
+        return ModelRegistry.is_cross_encoder_model(architectures)
+
 
 class CacheConfig:
     """Configuration for the KV cache.