RemoteStructServiceProvider Custom Header dose't sent to backend

[wangyuhuiever]

Steps to Reproduce
This is my code

import { Editor } from 'ketcher-react';
import 'ketcher-react/dist/index/css';
import { RemoteStructServiceProvider } from 'ketcher-core';

const structServiceProvider = new RemoteStructServiceProvider(
  'http://localhost:8002' + '/api/eln/ketcher/v2',  // this my proxy url to '/api/v2'
  {
  	'X-Token': 'token',
    'custom header': 'value', // optionally you can add custom headers object 
  },
);

const MyComponent = () => {
  console.log('headers', structServiceProvider.customHeaders);
  // log headers {X-Token: 'token', custom header: 'value'}
  structServiceProvider.customHeaders = { 'X-Value': 'value' }
  // this also does't show on browser request headers
  return (
    <Editor
      staticResourcesUrl={'/'}
      structServiceProvider={structServiceProvider}
    />
  );
};

Actual behavior
In the browser Request Headers, it doesn't show any X-Token, custom header, X-Value, and backend service doesn't recevice custom headers.
Expected behavior
The Browser send custom headers to backend.

Screenshots

Desktop (please complete the following information):

• OS: Ubuntu 22.04 and indigo-service in docker.
• Browser: Chrome, edge
• Version: 131.0.6.6778.140

Ketcher version [e.g. v2.4.2].
2.26.0 and 2.25.0

Test case
Add test case number (in EPMLSOPKET-* format) if bug was found during test case run.

Additional context
React 18.3.1

[wangyuhuiever]

I notice there are some routes without custom headers. /info is don't have, but /calculate with. So, I need split unauthorizad routes and authorizad routes, then proxy with different ways?