Wrong documentation for Elsa packages 3.3.4

on page https://elsa-workflows.github.io/elsa-documentation/elsa-studio.html#setup

In suggested Program.cs :

add :
```using Elsa.Studio.Models;```

replace :
```
builder.Services.AddRemoteBackend(
elsaClient => elsaClient.AuthenticationHandler = typeof(AuthenticatingApiHttpMessageHandler),
options => configuration.GetSection("Backend").Bind(options));
```

by :
```
builder.Services.AddRemoteBackend(
new BackendApiConfig
{
ConfigureBackendOptions = options => configuration.GetSection("Backend").Bind(options),
ConfigureHttpClientBuilder = options =>
options.AuthenticationHandler = typeof(AuthenticatingApiHttpMessageHandler),
}
);
```

Open the Elsa Studio setup page and locate the suggested Program.cs example for Elsa packages 3.3.4. Check the referenced package API, then update the example with the required Elsa.Studio.Models import and current AddRemoteBackend form. Done means the documentation matches the 3.3.4 API and the setup snippet is usable.

Written by the indexing model from the issue text.