feat(connector): [Checkout] add support for external authentication for checkout connector (#4006)
Co-authored-by: hrithikesh026 <hrithikesh.vm@juspay.in>
Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>
Co-authored-by: Hrithikesh <61539176+hrithikesh026@users.noreply.github.com>