fix: issue 1728 when useSuspense is false and default ns (#1731)

is custom, in strict mode only, memoization is performed of an unready translation function and is not refreshed after readiness.

The use of the isInitial ref is fundamentally incompatible with strict mode. Substituting ready instead seems to fix 1728 and keep both 1691 and 1718 fixed

react-i18next.js

@@ -687,13 +687,11 @@
 	      if (bindI18nStore && i18n) bindI18nStore.split(' ').forEach(e => i18n.store.off(e, boundReset));
 	    };
 	  }, [i18n, joinedNS]);
-	  const isInitial = react.useRef(true);
 	  react.useEffect(() => {
-	    if (isMounted.current && !isInitial.current) {
+	    if (isMounted.current && ready) {
 	      setT(getT);
 	    }
-	    isInitial.current = false;
-	  }, [i18n, keyPrefix]);
+	  }, [i18n, keyPrefix, ready]);
 	  const ret = [t, i18n, ready];
 	  ret.t = t;
 	  ret.i18n = i18n;