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_

Start with the StableDiffusionUpscaleLDM3DPipeline entry point and inspect the reported failure in configuration_utils.py around line 143. Reproduce the AttributeError with diffusers 0.28.0, then trace why the pipeline reaches the commented “upcast_vae” access. Done means the pipeline no longer raises this missing-attribute error in the reported reproduction.

Scritto dal modello di indicizzazione a partire dal testo della issue.