Fix: Improve Homebrew uninstallation feedback in 'mo remove'

When 'mole remove' is used and Mole was installed via Homebrew, the script
now provides more explicit feedback if the 'brew uninstall --force mole'
command fails. Previously, errors were silently ignored.

This change ensures that if Homebrew uninstallation encounters an issue,
the user is informed with the error output and instructed on how to
manually complete the uninstallation, preventing inconsistencies where
Homebrew still believes Mole is installed.

Additionally, a minor improvement to config_dir resolution in update_mole
was included for robustness.