fix: Account for rehydrated old users before language

closes #1819

app/hooks/useUserLocale.js

@@ -4,7 +4,7 @@ import useStores from "./useStores";
 export default function useUserLocale() {
   const { auth } = useStores();
 
-  if (!auth.user) {
+  if (!auth.user || !auth.user.language) {
     return undefined;
   }