Allow forcing encryption for not validated S/MIME certificates
This makes it possible to encrypt something for S/MIME certificates
that cannot be validated (e.g. because their root certificate is missing
or the CRL cannot be downloaded/checked).
(cherry picked from commit 8ca6e88dd4e5c21c6b8bd6ae21e3a389b3dd4c7e)
- GnuPG-bug-id: T6702