feat(client, i18n): add note about exam being available only in English (#53736)

Co-authored-by: Huyen Nguyen <25715018+huyenltnguyen@users.noreply.github.com>

client/i18n/locales/english/intro.json

@@ -1461,6 +1461,7 @@
     "go-back-to-learn": "Go back to the stable version of the curriculum.",
     "read-database-cert-article": "Please read this forum post before proceeding.",
     "enable-cookies": "You must enable third-party cookies before starting.",
-    "english-only": "The courses in this section are only available in English. We are only able to translate the titles and introductions at the moment, not the lessons themselves."
+    "english-only": "The courses in this section are only available in English. We are only able to translate the titles and introductions at the moment, not the lessons themselves.",
+    "exam-english-only": "Please note that the certification exam is currently available only in English. The rest of the courses are available in some languages."
   }
 }

client/src/templates/Introduction/components/legacy-links.tsx

@@ -2,7 +2,11 @@ import React from 'react';
 import { useTranslation } from 'react-i18next';
 import { Alert } from '@freecodecamp/ui';
 import { SuperBlocks } from '../../../../../shared/config/superblocks';
-import { isOldRespCert, isRelationalDbCert } from '../../../utils/is-a-cert';
+import {
+  isOldRespCert,
+  isRelationalDbCert,
+  isExamCert
+} from '../../../utils/is-a-cert';
 import { Link } from '../../../components/helpers';
 import { CodeAllyDown } from '../../../components/growth-book/codeally-down';
 
@@ -42,6 +46,12 @@ function LegacyLinks({ superBlock }: LegacyLinksProps): JSX.Element {
         )}
       </>
     );
+  } else if (isExamCert(superBlock) && clientLocale != 'english') {
+    return (
+      <Alert variant='info'>
+        <p>{t('intro:misc-text.exam-english-only')}</p>
+      </Alert>
+    );
   } else {
     return (
       <>

client/src/utils/is-a-cert.ts

@@ -7,3 +7,7 @@ export function isOldRespCert(superBlock: string): boolean {
 export function isRelationalDbCert(superBlock: string): boolean {
   return superBlock === String(SuperBlocks.RelationalDb);
 }
+
+export function isExamCert(superBlock: string): boolean {
+  return superBlock === String(SuperBlocks.FoundationalCSharp);
+}