Fix PyTorch tied weights being duplicated in the exported ONNX models (#1326)
* fix tied weights
* overwrite external data as well
* add transpose rather on MatMul node and not Gather
* update on review
* Update optimum/exporters/onnx/base.py
Co-authored-by: Joshua Lochner <admin@xenova.com>
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Co-authored-by: Joshua Lochner <admin@xenova.com>