testing: Enable mgf1 plugin for scenarios where FreeRADIUS uses PSS signatures

Looks like a cipher suite without DHE was selected previously.

Could be a side-effect of dc1085734f ("testing: Remove unnecessary
FreeRADIUS dh_file option as recommended in the log").

testing/tests/ikev2/rw-eap-peap-radius/hosts/carol/etc/strongswan.conf

@@ -5,5 +5,5 @@ swanctl {
 }
 
 charon-systemd {
-  load = random nonce aes md5 sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf vici kernel-netlink socket-default eap-identity eap-md5 eap-peap updown
+  load = random nonce aes md5 sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf mgf1 vici kernel-netlink socket-default eap-identity eap-md5 eap-peap updown
 }

testing/tests/ikev2/rw-eap-peap-radius/hosts/dave/etc/strongswan.conf

@@ -5,5 +5,5 @@ swanctl {
 }
 
 charon-systemd {
-  load = random nonce aes md5 sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf vici kernel-netlink socket-default eap-identity eap-md5 eap-peap updown
+  load = random nonce aes md5 sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf mgf1 vici kernel-netlink socket-default eap-identity eap-md5 eap-peap updown
 }

testing/tests/ikev2/rw-eap-ttls-radius/hosts/carol/etc/strongswan.conf

@@ -5,5 +5,5 @@ swanctl {
 }
 
 charon-systemd {
-  load = random nonce aes md5 sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf vici kernel-netlink socket-default eap-identity eap-md5 eap-ttls updown
+  load = random nonce aes md5 sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf mgf1 vici kernel-netlink socket-default eap-identity eap-md5 eap-ttls updown
 }

testing/tests/ikev2/rw-eap-ttls-radius/hosts/dave/etc/strongswan.conf

@@ -5,5 +5,5 @@ swanctl {
 }
 
 charon-systemd {
-  load = random nonce aes md5 sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf vici kernel-netlink socket-default eap-identity eap-md5 eap-ttls updown
+  load = random nonce aes md5 sha1 sha2 pem pkcs1 curve25519 gmp x509 curl revocation hmac kdf mgf1 vici kernel-netlink socket-default eap-identity eap-md5 eap-ttls updown
 }