#3487 Fix inpainting strength for various samplers (#3532)
* Throw error if strength adjusted num_inference_steps < 1
* Added new fast test to check ValueError raised when num_inference_steps < 1
when strength adjusts the num_inference_steps then the inpainting pipeline should fail
* fix #3487 initial latents are now only scaled by init_noise_sigma when pure noise
updated this commit w.r.t the latest merge here: https://github.com/huggingface/diffusers/pull/3533
* fix
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Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>
