Add 'ja' to deployedTranslations (#6351)

Author: smikitky

src/components/Seo.tsx

@@ -22,6 +22,7 @@ const deployedTranslations = [
   'zh-hans',
   'es',
   'fr',
+  'ja',
   // We'll add more languages when they have enough content.
   // Please DO NOT edit this list without a discussion in the reactjs/react.dev repo.
   // It must be the same between all translations.