[Misc] Consolidate ModelConfig code related to HF config (#10104)

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

vllm/config.py

@@ -15,7 +15,8 @@ from vllm.platforms import current_platform
 from vllm.tracing import is_otel_available, otel_import_error_traceback
 from vllm.transformers_utils.config import (ConfigFormat, get_config,
                                             get_hf_image_processor_config,
-                                            get_hf_text_config)
+                                            get_hf_text_config,
+                                            is_encoder_decoder, uses_mrope)
 from vllm.utils import (GiB_bytes, cuda_device_count_stateless, get_cpu_memory,
                         print_warning_once)
 
@@ -667,12 +668,13 @@ class ModelConfig:
         return self.multimodal_config
 
     @property
-    def is_encoder_decoder_model(self) -> bool:
+    def is_encoder_decoder(self) -> bool:
         """Extract the HF encoder/decoder model flag."""
-        return getattr(
-            self.hf_config, "is_encoder_decoder",
-            False) or (hasattr(self.hf_config, "text_config") and getattr(
-                self.hf_config.text_config, "is_encoder_decoder", False))
+        return is_encoder_decoder(self.hf_config)
+
+    @property
+    def uses_mrope(self) -> bool:
+        return uses_mrope(self.hf_config)
 
     @property
     def is_multimodal_model(self) -> bool: