cleanup: use `cleanup_path` more consistently
cleanup: use `cleanup_path` more consistently

`cleanup_path` already handles the dry-run logic, and also includes
those paths in the summary of space freed by `brew cleanup`.

Before this change:

    ❯ brew cleanup --dry-run
    Would remove: /Users/carlocab/Library/Caches/Homebrew/bootsnap (2,401 files, 41.9MB)

After this change:

    ❯ brew cleanup --dry-run
    Would remove: /Users/carlocab/Library/Caches/Homebrew/bootsnap (2,401 files, 41.9MB)
    ==> This operation would free approximately 41.9MB of disk space.

MikeMcQuaid/brew,Homebrew/brew,nandub/brew,JCount/brew,Homebrew/brew,JCount/brew,JCount/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,nandub/brew,Homebrew/brew,nandub/brew,MikeMcQuaid/brew,Homebrew/brew,nandub/brew,JCount/brew