(ui): increase nginx buffer size

react-ui/docker/webserver/nginx.conf

@@ -25,9 +25,9 @@ http {
 
     # Buffer size settings
     client_body_buffer_size 10K;
-    client_header_buffer_size 1k;
+    client_header_buffer_size 8k;
     client_max_body_size 8m;
-    large_client_header_buffers 2 1k;
+    large_client_header_buffers 4 8k;
 
     # File descriptor cache
     open_file_cache max=2000 inactive=20s;