[fix] fix mrope positions not picked up (#5265)

python/sglang/srt/openai_api/adapter.py

@@ -983,6 +983,8 @@ def v1_chat_generate_request(
                     ):
                         encoded = encoded[1:]
                     prompt_ids += encoded
+                if tokenizer_manager.model_config.is_multimodal:
+                    prompt = tokenizer_manager.tokenizer.decode(prompt_ids)
                 stop = request.stop
                 image_data = None
                 audio_data = None