Publicize: update connection `done` state once post publishes

Currently, when the post is published the `done` state is not updated on the fly. You need to do a hard refresh to get it.

It makes sense because the final sharing process is handled by an async job, on the server-side. But it doesn't mean we can't be optimistic and update the IU once the post is published, and theoretically, shared.

Also, the `done` state is reflected in the UI disabling the toggle button, that makes sense to do this immediately after the post is published beyond the final sharing result because the app should not allow re-sharing while the process is not done yet.