Fix brew bundle dump --global to respect XDG_CONFIG_HOME for initial Brewfile creation with backwards compatibility#20658

Copilot wants to merge 5 commits intomainHomebrew/brew:mainfrom

copilot/fix-brew-bundle-xdg-config-issueHomebrew/brew:copilot/fix-brew-bundle-xdg-config-issueCopy head branch name to clipboard