fix: init for vae during pixart tests (#6215)
* fix: init for vae during pixart tests
* print the values
* add flatten
* correct assertion value for test_inference
* correct assertion values for test_inference_non_square_images
* run styling
* debug test_inference_with_multiple_images_per_prompt
* fix assertion values for test_inference_with_multiple_images_per_prompt
