[v5] Remove deprecated tranformers.onnx (#41700)
* Remove deprecated tranformers.onnx
* Remove transformers.onnx related doc
* style
* shouldn't have been removed
* fix mismatch between metaclip2 modular en config file
* remove onnx config from not_doctested.txt
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Co-authored-by: Yih-Dar <2521628+ydshieh@users.noreply.github.com>
