Fix widget i18n missing locale files and clean up unused locales

- widget/i18n/index.js: only import en.json and zh_CN.json (the only
  locale files present); remove 40+ imports for missing locale JSONs
  that caused Vite compile failure and global white screen
- dashboard/i18n/index.js: remove unused locale imports for consistency
- Remove 62 unused locale JSON files from widget/i18n/locale/
- Minor: update index.html, test helpers, e2e test, languages spec

frontend/app/javascript/dashboard/components/widgets/conversation/advancedFilterItems/specs/languages.spec.js

@@ -2,7 +2,7 @@ import { getLanguageName, getLanguageDirection } from '../languages';
 
 describe('#getLanguageName', () => {
   it('Returns correct language name', () => {
-    expect(getLanguageName('es')).toEqual('Spanish');
+    expect(getLanguageName('zh')).toEqual('Chinese');
     expect(getLanguageName()).toEqual('');
     expect(getLanguageName('rrr')).toEqual('');
     expect(getLanguageName('')).toEqual('');
@@ -11,7 +11,7 @@ describe('#getLanguageName', () => {
 
 describe('#getLanguageDirection', () => {
   it('Returns correct language direction', () => {
-    expect(getLanguageDirection('es')).toEqual(false);
+    expect(getLanguageDirection('en')).toEqual(false);
     expect(getLanguageDirection('ar')).toEqual(true);
   });
 });

frontend/app/javascript/dashboard/i18n/index.js

@@ -1,85 +1,7 @@
-import ar from './locale/ar';
-import bg from './locale/bg';
-import ca from './locale/ca';
-import cs from './locale/cs';
-import da from './locale/da';
-import de from './locale/de';
-import el from './locale/el';
 import en from './locale/en';
-import es from './locale/es';
-import et from './locale/et';
-import fa from './locale/fa';
-import fi from './locale/fi';
-import fr from './locale/fr';
-import he from './locale/he';
-import hi from './locale/hi';
-import hu from './locale/hu';
-import id from './locale/id';
-import it from './locale/it';
-import ja from './locale/ja';
-import ko from './locale/ko';
-import lv from './locale/lv';
-import ml from './locale/ml';
-import nl from './locale/nl';
-import no from './locale/no';
-import pl from './locale/pl';
-import pt from './locale/pt';
-import pt_BR from './locale/pt_BR';
-import ro from './locale/ro';
-import ru from './locale/ru';
-import sk from './locale/sk';
-import sr from './locale/sr';
-import sv from './locale/sv';
-import ta from './locale/ta';
-import th from './locale/th';
-import tr from './locale/tr';
-import uk from './locale/uk';
-import vi from './locale/vi';
 import zh_CN from './locale/zh_CN';
-import zh_TW from './locale/zh_TW';
-import is from './locale/is';
-import lt from './locale/lt';
 
 export default {
-  ar,
-  bg,
-  ca,
-  cs,
-  da,
-  de,
-  el,
   en,
-  es,
-  et,
-  fa,
-  fi,
-  fr,
-  he,
-  hi,
-  hu,
-  id,
-  it,
-  ja,
-  ko,
-  ml,
-  lv,
-  nl,
-  no,
-  pl,
-  pt_BR,
-  pt,
-  ro,
-  ru,
-  sk,
-  sr,
-  sv,
-  ta,
-  th,
-  tr,
-  uk,
-  vi,
   zh_CN,
-  zh_TW,
-  is,
-  lt,
 };