Returns incorrect content type for Inference Endpoints

I played around with my own Inference Endpoint using _stabilityai/stable-diffusion-xl-base-1.0_ and the Inference API. The second one worked, my own Endpoint did not. In fact, the wrong content type (test/plain) seems to be delivered at the Inference Endpoints if it is not requested in the header. Just add a **"Accept": "image/png"** to the request header [here](https://github.com/jbilcke-hf/ai-comic-factory/blob/main/src/app/engine/render.ts#L259-L262), rebuild and everything works fine again.