docs(admin): openapi custom data provider example

[igornast]

The pull request enhances the documentation for the Admin section by adding a comprehensive example of a custom dataProvider.

Goal:
To provide a more advanced, real-world example for developers who need to extend the OpenApiAdmin component with custom authentication and error handling.

[igornast]

@vinceAmstoutz could you take a look here? 👀

[vinceAmstoutz]

Thanks!

Sounds good to me @igornast except for a few minor changes. To be sure I'll ask people who know more about the API Platform front-end and admin components.

[alanpoulain]

Suggested change

console.log('HTTP Response:', { status, headers, body, json });

[igornast]

@alanpoulain for the sake of example, we can even remove the whole try/catch clause. Maybe it makes more sense to keep it short here.

  [...]
  if (token) {
    options.user = { token: `Bearer ${token}`, authenticated: true };
  }
  
return await fetchUtils.fetchJson(url, options);
}

[alanpoulain]

Sure, it would be simpler!

[alanpoulain]

Maybe it would be better to add it to the authentication support page, wouldn't it?

[igornast]

@alanpoulain just a quick update - I'm reviewing the authentication support page to see if there is a space for improvement by simplifying the example. I find the current version a bit hard to read and understand.

[igornast]

@alanpoulain Please let me know if you find that structure readable and helpful. Comments and suggestions are welcome. :)

[alanpoulain]

I think it could be improved, especially the JWT section (not shared with the Hydra part), but it's already an improvement, thank you.

[igornast]

@alanpoulain @vinceAmstoutz many thanks for your support. 🚀 ❤️