nixos/nextcloud: remove X-XSS-Protection

see nextcloud/server#53476

Author: dotlambda

nixos/modules/services/web-apps/nextcloud.nix

@@ -1531,7 +1531,6 @@ in
             index index.php index.html /index.php$request_uri;
             ${lib.optionalString (cfg.nginx.recommendedHttpHeaders) ''
               add_header X-Content-Type-Options nosniff;
-              add_header X-XSS-Protection "1; mode=block";
               add_header X-Robots-Tag "noindex, nofollow";
               add_header X-Permitted-Cross-Domain-Policies none;
               add_header X-Frame-Options sameorigin;