bugfix: Ensure schema is loaded before processing (#221) * bugfix: Ensure schema is loaded before processing Schema wasn't loaded prior to processing the input paths this resulted in a noop nil response. To ensure we always load the schema first we now block on runner ready state before processing. Additionaly a nil doc is considered an error. In the cases we call ProcessInputPaths we can accept that error; in manager we explicitly check for doc being nil and emit an error log. * Ensure that we always 202 for async Async predictions should not 500. However, since we now known that the runner failed before we send the prediction request down, we end up needing to work around the error and still send a 202 *then* let the webhook indicate failure. While this behavior is somewhat crazy, it is the behavioral contract we can revisit in the future.