test_sshd.test: sync an option with sshd_config used in Dockerfile

Follow-up to d4690e9509 #1024

Closes #2481

tests/test_sshd.test

@@ -86,6 +86,7 @@ chmod go-rwx \
   -o 'PidFile sshd.pid' \
   -o "AuthorizedKeysFile ${PUBKEY} ${d}/openssh_server/authorized_keys" \
   -o "TrustedUserCAKeys ${cakeys}" \
+  -o 'KbdInteractiveAuthentication yes' \
   -o 'PermitRootLogin yes' \
   -D \
   ${SSHD_FLAGS} &