[Refactor] Remove get_encoder_dummy_data (#32241)

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

vllm/multimodal/processing.py

@@ -1396,6 +1396,10 @@ class BaseProcessingInfo:
         """
         return self.ctx.get_hf_processor(**kwargs)
 
+    @property
+    def skip_prompt_length_check(self) -> bool:
+        return False
+
     @abstractmethod
     def get_supported_mm_limits(self) -> Mapping[str, int | None]:
         """
@@ -2403,10 +2407,6 @@ class EncDecMultiModalProcessor(BaseMultiModalProcessor[_I]):
         """
         raise NotImplementedError
 
-    @property
-    def pad_dummy_encoder_prompt(self) -> bool:
-        return False
-
     def create_decoder_prompt(
         self,
         prompt: str | list[int],