Forward-compatibility fallback for LatticeStripe.ExternalAccount responses
whose object is neither "bank_account" nor "card". Preserves the raw
payload in :extra so user code does not crash on a new Stripe object type.
Callers should match %LatticeStripe.BankAccount{} or %LatticeStripe.Card{}
first and treat %LatticeStripe.ExternalAccount.Unknown{} as an escape hatch:
case ea do
%LatticeStripe.BankAccount{} -> handle_bank(ea)
%LatticeStripe.Card{} -> handle_card(ea)
%LatticeStripe.ExternalAccount.Unknown{} = u ->
Logger.warning("unknown external account type: #{u.object}")
end