Move `RequestState` logic from lemmy-ui into lemmy-js-client

Currently lemmy-ui uses some really overly complicated logic to create a `wrappedClient` so it can interpret the responses as request states. We should get rid of this so that lemmy-ui doesn't need to use a wrapped-client, and can just use `LemmyHttp` directly. Context: https://github.com/LemmyNet/lemmy-ui/pull/4025