app: AppConfigurator default client creation should not fall back to service discovery

In `packages/modules/app/src/AppConfigurator.ts`, `_createHttpClient` falls back to creating a client via the `serviceDiscovery` module when the http provider hasn't configured one, with a comment noting this should be removed once the portal service is refactored.

```ts
// TODO - remove when refactor portal service!
/** resolve and create a client from discovery */
return await serviceDiscovery.createClient(serviceName);
```

Open packages/modules/app/src/AppConfigurator.ts and read _createHttpClient, focusing on the serviceDiscovery fallback and its TODO comment. Confirm how the HTTP provider configuration is handled, then remove the fallback so an unconfigured provider no longer creates a discovery client; done means this path no longer calls serviceDiscovery.createClient.

Written by the indexing model from the issue text.