fix(client): update navbar for Chinese Simplified and Traditional (#42007)

* fix: navbar bug

Should resolve the current bug on staging with the nav bar.

* fix: update display names

Update the display names for the two Chinese options.

* fix(tools): remove extraneous test

Docs do not indicate that language code needs to be 2 characters.

client/i18n/locales.test.js

@@ -1,7 +1,6 @@
 /* global expect */
 import {
   availableLangs,
-  i18nextCodes,
   langDisplayNames,
   langCodes
 } from '../../config/i18n/all-langs';
@@ -45,10 +44,6 @@ describe('Locale tests:', () => {
         });
       });
 
-      test(`has a two character entry in the i18nextCodes variable`, () => {
-        expect(i18nextCodes[lang].length).toBe(2);
-      });
-
       test(`has an entry in the langDisplayNames variable`, () => {
         expect(langDisplayNames[lang].length).toBeGreaterThan(0);
       });