nixos/forgejo: fix typo in builtin ssh server conditional

This conditional was introduced in 402b5c67a8
and is supposed to check for `server.START_SSH_SERVER` but instead
checked for `START_SSH_SERVER`.

Co-Authored-By: Pyrox <pyrox@pyrox.dev>

nixos/modules/services/misc/forgejo.nix

@@ -789,7 +789,9 @@ in
       } // lib.listToAttrs (map (e: lib.nameValuePair e.env "%d/${e.env}") secrets);
     };
 
-    services.openssh.settings.AcceptEnv = mkIf (!cfg.settings.START_SSH_SERVER or false) "GIT_PROTOCOL";
+    services.openssh.settings.AcceptEnv = mkIf (
+      !cfg.settings.server.START_SSH_SERVER or false
+    ) "GIT_PROTOCOL";
 
     users.users = mkIf (cfg.user == "forgejo") {
       forgejo = {