feat: add flux kontext

[jlonge4]

What does this PR do?

This adds flux-kontext to the AUTO_TEXT2IMAGE_PIPELINES_MAPPING. This enables Flux Kontext to be used for text -> img when using optimum neuron. Ref: huggingface/optimum-neuron#815
Sister PR:
huggingface/optimum-neuron#916

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Who can review?

@yiyixuxu and @asomoza

[HuggingFaceDocBuilderDev]

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[asomoza]

thanks! primarily Kontext is for Image2Image so I think it makes more sense to add it there than to Text2Image though

[jlonge4]

@asomoza thoughts on adding it to both, like vanilla flux?

[asomoza]

yeah, it's also fine to add it to both since it can be used for both tasks

[asomoza]

@bot /style

[github-actions]

Style bot fixed some files and pushed the changes.