When booting from initramfs ("ospkg_fetch_metod": "initramfs" in trust policy), don't require https config

Currently, attempting to boot from an os package in the initramfs fails if https root certs are missing,"[ERROR] HTTPS root certificates: open /etc/ssl/certs/isrgrootx1.pem: no such file or directory".

It doesn't make much sense to require presence of a file which isn't going to be used. And in this case, maybe stboot shouldn't even configure the network or require corresponding config settings to be present and valid?