Add language: Frisian (#8214)

* Update app.config.js

* Update lingui.config.js

* Update dates.ts

* Update helpers.ts

* Update i18n.ts

* Update i18n.web.ts

* Update languages.ts

* Create messages.po

src/locale/helpers.ts

@@ -181,6 +181,8 @@ export function sanitizeAppLanguageSetting(appLanguage: string): AppLanguage {
         return AppLanguage.fi
       case 'fr':
         return AppLanguage.fr
+      case 'fy':
+        return AppLanguage.fy
       case 'ga':
         return AppLanguage.ga
       case 'gd':