Handle 403 responses

[alejandrodob]

Improve the way we handle a 403 response, because it may be given by an already answered task, so it should maybe just bypass that answer and just request a new task without any impact to the user, instead of hanging like it does now.

[alejandrodob]

I have been trying to fix this. There's no easy way of telling a user has already answered a task from JS directly, and checking only a 403 response could hide other reasons, like if a project is hidden, etc. I believe this may be better to handle the responses directly from the presenter code. So I'm closing this for now.