Fix save_path bug in textual inversion training script (#4710)
* Update textual_inversion.py
fixed safe_path bug in textual inversion training
* Update test_examples.py
update test_textual_inversion for updating saved file's name
* Update textual_inversion.py
fixed some formatting issues
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Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>