text: Title: [Bug] ImportError: cannot import name 'is_valid_list_of_images' from transformers.models.mllama.image_processing_mllama
  Body: ### Checklist
  
  - [x] 1. I have searched related issues but cannot get the expected help.
  - [x] 2. The bug has not been fixed in the latest version.
  - [x] 3. Please note that if the bug-related issue you submitted lacks corresponding environment info and a minimal reproducible demo, it will be challenging for us to reproduce and resolve the issue, reducing the likelihood of receiving feedback.
  - [x] 4. If the issue you raised is not a bug but a question, please raise a discussion at https://github.com/sgl-project/sglang/discussions/new/choose Otherwise, it will be closed.
  - [x] 5. Please use English, otherwise it will be closed.
  
  ### Describe the bug
  
  ```
  python -msglang.launch_server --help
  Traceback (most recent call last):
    File "<frozen runpy>", line 198, in _run_module_as_main
    File "<frozen runpy>", line 88, in _run_code
    File "/scratch/xxxx/sglang/venv/lib/python3.11/site-packages/sglang/launch_server.py", line 6, in <module>
      from sglang.srt.entrypoints.http_server import launch_server
    File "/scratch/xxxx/sglang/venv/lib/python3.11/site-packages/sglang/srt/entrypoints/http_server.py", line 41, in <module>
      from sglang.srt.entrypoints.engine import _launch_subprocesses
    File "/scratch/xxxx/sglang/venv/lib/python3.11/site-packages/sglang/srt/entrypoints/engine.py", line 36, in <module>
      from sglang.srt.managers.data_parallel_controller import (
    File "/scratch/xxxx/sglang/venv/lib/python3.11/site-packages/sglang/srt/managers/data_parallel_controller.py", line 27, in <module>
      from sglang.srt.managers.io_struct import (
    File "/scratch/xxxx/sglang/venv/lib/python3.11/site-packages/sglang/srt/managers/io_struct.py", line 24, in <module>
      from sglang.srt.managers.schedule_batch import BaseFinishReason
    File "/scratch/xxxx/sglang/venv/lib/python3.11/site-packages/sglang/srt/managers/schedule_batch.py", line 42, in <module>
      from sglang.srt.configs.model_config import ModelConfig
    File "/scratch/xxxx/sglang/venv/lib/python3.11/site-packages/sglang/srt/configs/__init__.py", line 4, in <module>
      from sglang.srt.configs.qwen2_5_vl_config import (
    File "/scratch/xxxx/sglang/venv/lib/python3.11/site-packages/sglang/srt/configs/qwen2_5_vl_config.py", line 51, in <module>
      from transformers.models.mllama.image_processing_mllama import is_valid_list_of_images
  ImportError: cannot import name 'is_valid_list_of_images' from 'transformers.models.mllama.image_processing_mllama' (/scratch/xxxx/sglang/venv/lib/python3.11/site-packages/transformers/models/mllama/image_processing_mllama.py)
  
  ```
  
  ### Reproduction
  
  sglang: 0.4.3.post2
  transformers: 4.49.0
  
  ### Environment
  
  Python: 3.11.11 | packaged by conda-forge | (main, Dec  5 2024, 14:17:24) [GCC 13.3.0]
  CUDA available: True
  GPU 0: NVIDIA H200
  GPU 0 Compute Capability: 9.0
  CUDA_HOME: None
  PyTorch: 2.5.1+cu124
  sglang: 0.4.3.post2
  sgl_kernel: 0.0.3.post6
  flashinfer: 0.2.2+cu124torch2.5
  triton: 3.1.0
  transformers: 4.49.0
  torchao: 0.8.0
  numpy: 1.26.4
  aiohttp: 3.11.13
  fastapi: 0.115.8
  hf_transfer: 0.1.9
  huggingface_hub: 0.29.1
  interegular: 0.3.3
  modelscope: 1.23.1
  orjson: 3.10.15
  packaging: 24.2
  psutil: 7.0.0
  pydantic: 2.10.6
  multipart: 0.0.20
  zmq: 26.2.1
  uvicorn: 0.34.0
  uvloop: 0.21.0
  vllm: 0.7.2
  openai: 1.64.0
  tiktoken: 0.9.0
  anthropic: 0.47.2
  decord: 0.6.0
  