QuantizedFluxTransformer2DModel save bug

### Describe the bug

QuantizedFluxTransformer2DModel save bug

### Reproduction

```
class QuantizedFluxTransformer2DModel(QuantizedDiffusersModel):
base_class = FluxTransformer2DModel

transformer = FluxTransformer2DModel.from_pretrained(
'black-forest-labs/FLUX.1-Fill-dev', subfolder="transformer", torch_dtype=torch.bfloat16,
).to("cuda")

qtransformer = QuantizedFluxTransformer2DModel.quantize(transformer, weights=qfloat8)

# for param in qtransformer.parameters(): param.data = param.data.contiguous() # useless

qtransformer.save_pretrained('fluxfill_transformer_fp8')
```

### Logs

```shell
ValueError: You are trying to save a non contiguous tensor: `time_text_embed.timestep_embedder.linear_1.weight._data` which is not allowed. It either means you are trying to save tensors which are reference of each other in which case it's recommended to save only the full tensors, and reslice at load time, or simply call `.contiguous()` on your tensor to pack it before saving.
```

### System Info

python==3.12
torch==2.4.0 + cu121
transformers==4.47.0
optimum-quanto==0.2.6
diffusers main from 12.23

### Who can help?

_No response_