pixi clean cache --exec doesn't fail when permission denied

[pavelzw]

Checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pixi, using pixi --version.

Reproducible example

❯ pixi exec python --version
Python 3.13.1
❯ chmod 755 /Users/pavel/Library/Caches/rattler/cache/cached-envs-v0
❯ sudo chown root:wheel /Users/pavel/Library/Caches/rattler/cache/cached-envs-v0
❯ touch /Users/pavel/Library/Caches/rattler/cache/cached-envs-v0/test
touch: /Users/pavel/Library/Caches/rattler/cache/cached-envs-v0/test: Permission denied
❯ pixi clean cache --exec
  removed /Users/pavel/Library/Caches/rattler/cache/cached-envs-v0                                                                                                                                                  
❯ ls /Users/pavel/Library/Caches/rattler/cache/cached-envs-v0
python-4d883ede1a0315d/

Issue description

pixi exits without failing

Expected behavior

pixi should failed or at least print a warning that not everything could be deleted