Fixed invalid pipeline_class_name parameter.

[aihao2000]

What does this PR do?

Fixed invalid pipeline_class_name parameter.
In the original convert script, the pipeline_class_name argument is not working. I found this problem when I tried to convert the sdxl model. If I don't try to change the pipeline type, I'll get TypeError: StableDiffusionPipeline.init() got an unexpected keyword argument 'text_encoder_2'. Change the code is passed to pipeline_class_name =" StableDiffusionXLPipeline " it can work normally.

Fixes # (issue)
#4562

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[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.

[yiyixuxu]

thank you!