Passing `cross_attention_kwargs` to `StableDiffusionInstructPix2PixPipeline`

[AlexeyZhuravlev]

Add cross_attention_kwargs to __call__ method of StableDiffusionInstructPix2PixPipeline, which are passed to UNet.

What does this PR do?

Implements https://github.com/huggingface/diffusers/issues/7962

Adding ability to pass custom cross-attention arguments for UNet. This allows all the same functionality with cross-attention manipulations as inside StableDiffusionPipeline: LoRAs, custom adapters, etc.

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