Allow forcing encryption result as not compliant

This is done when an S/MIME encryption is performed without certificate
validation. Ideally, we'd check the compliance of the encryption result
reported by GnuPG, but that doesn't seem to be reliable if "always-trust"
is used. And information about the compliance of the encryption result is
only available since today in GpgME so that we couldn't use it anyway.

• GnuPG-bug-id: T6702