As mentioned in the linked Debian bug, selecting "Configure encrypted volumes" ought to make it possible to use your existing encrypted volumes after entry of a passphrase, rather than merely saying "is it OK if we destroy your data?".
As mentioned in the linked Debian bug, selecting "Configure encrypted volumes" ought to make it possible to use your existing encrypted volumes after entry of a passphrase, rather than merely saying "is it OK if we destroy your data?".