StableDiffusionUpscaleLDM3DPipeline object has no attribute 'upcast_vae'

### Describe the bug

[miniconda3/lib/python3.12/site-packages/diffusers/configuration_utils.py:143](https://vscode-remote+ssh-002dremote-002b10-002e155-002e234-002e172.vscode-resource.vscode-cdn.net/data2/miniconda3/lib/python3.12/site-packages/diffusers/configuration_utils.py:143), in ConfigMixin.__getattr__(self, name)
[140](https://vscode-remote+ssh-002dremote-002b10-002e155-002e234-002e172.vscode-resource.vscode-cdn.net/data2/miniconda3/lib/python3.12/site-packages/diffusers/configuration_utils.py:140) deprecate("direct config name access", "1.0.0", deprecation_message, standard_warn=False)
[141](https://vscode-remote+ssh-002dremote-002b10-002e155-002e234-002e172.vscode-resource.vscode-cdn.net/data2/miniconda3/lib/python3.12/site-packages/diffusers/configuration_utils.py:141) return self._internal_dict[name]
--> [143](https://vscode-remote+ssh-002dremote-002b10-002e155-002e234-002e172.vscode-resource.vscode-cdn.net/data2/miniconda3/lib/python3.12/site-packages/diffusers/configuration_utils.py:143) raise AttributeError(f"'{type(self).__name__}' object has no attribute '{name}'")

AttributeError: 'StableDiffusionUpscaleLDM3DPipeline' object has no attribute 'upcast_vae'

### Reproduction

The code has commented 'upcast_vae'

### Logs

_No response_

### System Info

0.28.0

### Who can help?

_No response_

Comienza con el punto de entrada StableDiffusionUpscaleLDM3DPipeline e inspecciona el fallo notificado en configuration_utils.py alrededor de la línea 143. Reproduce el AttributeError con diffusers 0.28.0 y, después, rastrea por qué la pipeline llega al acceso comentado a “upcast_vae”. Se considera completado cuando la pipeline ya no produce este error de atributo ausente en la reproducción notificada.

Escrito por el modelo de indexación a partir del texto del issue.