Ran successfully to completion. But on a repeat run `convert_unclip` didn't pass the hash check for some reason.
- fix inpainting model download urls
- shows a progress bar for downloads
- skips downloading existing files
- uses a temporary file to prevent partial downloads
- can do a dry run to check if url is valid `DRY_RUN=1 python scripts/prepare_test_weights.py`
- displays the downloaded file hash
