Remove fib service should use a feature flag

## Requirements

- [ ] Update the remote fib service to use the same feature flag as [the main app](https://github.com/open-feature/playground/blob/028fde0e9034450ce95cc31e5756b87f51514e08/packages/fibonacci-service/src/app/app.controller.ts#L11)
- [ ] Send the required evaluation context to the remote service
- [ ] Set the evaluation context on the request in the remote service