### What happened?

When using `azure_ai/flux.2-pro` for image editing via `/v1/images/edits`, the reference image is silently ignored. FLUX generates a completely new image from the prompt instead of editing the provided reference image.

The root cause is in `litellm/llms/azure_ai/image_edit/flux2_transformation.py`. The `transform_image_edit_request` method sends the base64-encoded image under the JSON key `"image"`, but the Black Forest Labs API on Azure AI Foundry expects `"input_image"`.

The API does not return an error. It simply ignores the unknown `"image"` field and generates a new image from scratch, making the bug hard to detect.

I verified this by patching line 113 from `"image"` to `"input_image"` in a running LiteLLM proxy container. With the fix, the reference image is correctly preserved and edited. Without it, a completely different image is generated.

**References:** - [Azure Foundry FLUX Guide](https://learn.microsoft.com/en-us/azure/foundry/foundry-models/how-to/use-foundry-models-flux) - [BFL Image Editing Docs](https://docs.bfl.ml/flux_2/flux2_image_editing)

### Steps to Reproduce

1. Configure `azure_ai/flux.2-pro` in config.yaml: ```yaml - model_name: f…