Don't retrieve user info from blocked instances

plume-models/src/remote_fetch_actor.rs

@@ -45,6 +45,9 @@ impl Actor for RemoteFetchActor {
             RemoteUserFound(user) => match self.conn.get() {
                 Ok(conn) => {
                     let conn = DbConn(conn);
+                    if user.get_instance(&conn).map_or(false, |instance| instance.blocked) {
+                        return;
+                    }
                     // Don't call these functions in parallel
                     // for the case database connections limit is too small
                     fetch_and_cache_articles(&user, &conn);