fix: update nginx config

resources/klipper_webui_nginx.cfg

@@ -23,8 +23,7 @@ server {
     index index.html;
     server_name _;
 
-    #max upload size for gcodes (0 = no limit)
-    client_max_body_size 0;
+    proxy_request_buffering off;
 
     location / {
         try_files $uri $uri/ /index.html;