`urls` config ignored when set in a config file provided through configURL

Demonstration API definition

Test using the petstore API def

Configuration (browser query string, constructor, config.yaml)

See below

Expected Behavior

When trying to configure the urls params provided in a configURL, it is ignored.
The following message is displayed: "No API definition provided."

Index HTML:

const ui = SwaggerUIBundle({
    configUrl: "./swagger-config.json"
});

JSON Configuration:

{
        dom_id: "#swagger-ui",
        deepLinking: true,
        presets: [SwaggerUIBundle.presets.apis, SwaggerUIStandalonePreset],
        plugins: [SwaggerUIBundle.plugins.DownloadUrl],
        layout: "StandaloneLayout",
        urls: [
            {
                name: "test",
                url: "http://petstore.swagger.io/v2/swagger.json"
            }
        ]
    }

When I use the same configuration directly in the HTML, the urls is well considered.

Start by tracing how the index HTML loads configUrl and how the external swagger-config.json is merged into Swagger UI settings. Verify the handling of the urls configuration by reproducing the issue with the provided petstore URL; done means the API selector loads and the definition is displayed when urls is supplied through configUrl.