What does this PR do?

config attribute not foud error for FluxMultiControlNetModel Pipeline for multi controlnet solved with same implementation huggingface#9586 with yiyixuxu suggestion in huggingface#9534

Fixes huggingface#9534 (issue)

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline?
• Did you read our philosophy doc (important for complex PRs)?
• Was this discussed/approved via a GitHub issue or the forum? Please add a link to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the
  documentation guidelines, and
  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

@yiyixuxu
@sayakpaul

If you know how to use git blame, that is the easiest way, otherwise, here is a rough guide of who to tag.
Please tag fewer than 3 people.

Core library:

• Schedulers: @yiyixuxu
• Pipelines and pipeline callbacks: @yiyixuxu and @asomoza
• Training examples: @sayakpaul
• Docs: @stevhliu and @sayakpaul
• JAX and MPS: @pcuenca
• Audio: @sanchit-gandhi
• General functionalities: @sayakpaul @yiyixuxu @DN6

Integrations:

• deepspeed: HF Trainer/Accelerate: @SunMarc
• PEFT: @sayakpaul @BenjaminBossan

HF projects:

• accelerate: different repo
• datasets: different repo
• transformers: different repo
• safetensors: different repo

-->