`device_map="auto"` supported for diffusers pipelines?

### Describe the bug

Hey dear diffusers team,

for `DiffusionPipline`, as I understand (hopefully correctly) from [this part of the documentation](https://huggingface.co/docs/diffusers/v0.33.1/en/api/pipelines/overview#diffusers.DiffusionPipeline.from_pretrained.device_map), it should be possible to specify `device_map="auto"` when loading a pipeline with `from_pretrained` but this results in a value error saying that this is not supported.

However, the documentation on [device placement](https://huggingface.co/docs/diffusers/en/tutorials/inference_with_big_models#device-placement) currently states that only the "balanced" strategy is supported.

Is this possibly similar to #11432 and should be removed from the docstrings / documentation? Happy to help on this with a PR if it turns out to be a mistake in the documentation.

Thanks a lot for your hard work!

### Reproduction

```python
from diffusers import DiffusionPipeline
pipeline = DiffusionPipeline.from_pretrained("stable-diffusion-v1-5/stable-diffusion-v1-5", device_map="auto")
```

or

```python
from diffusers import StableDiffusionPipeline
pipe = StableDiffusionPipeline.from_pretrained("stable-diffusion-v1-5/stable-diffusion-v1-5", device_map="auto")
```

### Logs

```shell
---------------------------------------------------------------------------
NotImplementedError Traceback (most recent call last)
Cell In[12], line 3
1 from diffusers import StableDiffusionPipeline
----> 3 pipe = StableDiffusionPipeline.from_pretrained("stable-diffusion-v1-5/stable-diffusion-v1-5", device_map="auto")

File ~/miniconda3/envs/pruna/lib/python3.10/site-packages/huggingface_hub/utils/_validators.py:114, in validate_hf_hub_args.._inner_fn(*args, **kwargs)
111 if check_use_auth_token:
112 kwargs = smoothly_deprecate_use_auth_token(fn_name=fn.__name__, has_token=has_token, kwargs=kwargs)
--> 114 return fn(*args, **kwargs)

File ~/miniconda3/envs/pruna/lib/python3.10/site-packages/diffusers/pipelines/pipeline_utils.py:745, in DiffusionPipeline.from_pretrained(cls, pretrained_model_name_or_path, **kwargs)
742 raise ValueError("`device_map` must be a string.")
744 if device_map is not None and device_map not in SUPPORTED_DEVICE_MAP:
--> 745 raise NotImplementedError(
746 f"{device_map} not supported. Supported strategies are: {', '.join(SUPPORTED_DEVICE_MAP)}"
747 )
749 if device_map is not None and device_map in SUPPORTED_DEVICE_MAP:
750 if is_accelerate_version("<", "0.28.0"):

NotImplementedError: auto not supported. Supported strategies are: balanced
```

### System Info

- 🤗 Diffusers version: 0.33.1
- Platform: Linux-5.15.0-139-generic-x86_64-with-glibc2.35
- Running on Google Colab?: No
- Python version: 3.10.16
- PyTorch version (GPU?): 2.7.0+cu126 (True)
- Flax version (CPU?/GPU?/TPU?): not installed (NA)
- Jax version: not installed
- JaxLib version: not installed
- Huggingface_hub version: 0.30.2
- Transformers version: 4.51.3
- Accelerate version: 1.6.0
- PEFT version: 0.15.2
- Bitsandbytes version: 0.45.5
- Safetensors version: 0.5.3
- xFormers version: not installed
- Accelerator: NVIDIA H100 PCIe, 81559 MiB
NVIDIA H100 PCIe, 81559 MiB
- Using GPU in script?: yes
- Using distributed or parallel set-up in script?: yes

### Who can help?

_No response_