'BitDiffusion' object has no attribute 'scheduler'

### Describe the bug

Running the [Bit Diffusion](https://github.com/huggingface/diffusers/blob/main/examples/community/README.md#bit-diffusion) example code from the Community Pipeline Examples fails

### Reproduction

```
from diffusers import DiffusionPipeline
pipe = DiffusionPipeline.from_pretrained("google/ddpm-cifar10-32", custom_pipeline="bit_diffusion")
image = pipe().images[0]
```

### Logs

```shell
AttributeError Traceback (most recent call last)
in ()
1 from diffusers import DiffusionPipeline
----> 2 pipe = DiffusionPipeline.from_pretrained("google/ddpm-cifar10-32", custom_pipeline="bit_diffusion")
3 image = pipe().images[0]

/usr/local/lib/python3.10/dist-packages/huggingface_hub/utils/_validators.py in _inner_fn(*args, **kwargs)
112 kwargs = smoothly_deprecate_use_auth_token(fn_name=fn.__name__, has_token=has_token, kwargs=kwargs)
113
--> 114 return fn(*args, **kwargs)
115
116 return _inner_fn # type: ignore

/usr/local/lib/python3.10/dist-packages/diffusers/pipelines/pipeline_utils.py in from_pretrained(cls, pretrained_model_name_or_path, **kwargs)
964
965 # 10. Instantiate the pipeline
--> 966 model = pipeline_class(**init_kwargs)
967
968 # 11. Save where the model was instantiated from

~/.cache/huggingface/modules/diffusers_modules/git/bit_diffusion.py in __init__(self, unet, scheduler, bit_scale)
220 super().__init__()
221 self.bit_scale = bit_scale
--> 222 self.scheduler.step = (
223 ddim_bit_scheduler_step if isinstance(scheduler, DDIMScheduler) else ddpm_bit_scheduler_step
224 )

/usr/local/lib/python3.10/dist-packages/diffusers/configuration_utils.py in __getattr__(self, name)
141 return self._internal_dict[name]
142
--> 143 raise AttributeError(f"'{type(self).__name__}' object has no attribute '{name}'")
144
145 def save_config(self, save_directory: Union[str, os.PathLike], push_to_hub: bool = False, **kwargs):

AttributeError: 'BitDiffusion' object has no attribute 'scheduler'
```

### System Info

- 🤗 Diffusers version: 0.30.0
- Platform: Linux-6.1.85+-x86_64-with-glibc2.35
- Running on Google Colab?: Yes
- Python version: 3.10.12
- PyTorch version (GPU?): 2.3.1+cu121 (False)
- Flax version (CPU?/GPU?/TPU?): 0.8.4 (cpu)
- Jax version: 0.4.26
- JaxLib version: 0.4.26
- Huggingface_hub version: 0.23.5
- Transformers version: 4.42.4
- Accelerate version: 0.32.1
- PEFT version: not installed
- Bitsandbytes version: not installed
- Safetensors version: 0.4.3
- xFormers version: not installed
- Accelerator: NA
- Using GPU in script?: no
- Using distributed or parallel set-up in script?: no

### Who can help?

@patrickvonplaten (https://github.com/huggingface/diffusers/commit/78a6eed2d7b082d8116c23061b57621cf909320f) @kingstut (https://github.com/huggingface/diffusers/pull/971)