Update translation files

Updated by "Cleanup translation files" hook in Weblate.

Translation: Mobilizon/Frontend
Translate-URL: https://weblate.framasoft.org/projects/mobilizon/frontend/

js/src/i18n/langs.json

@@ -1,8 +1,5 @@
 {
-  "cs": "čeština",
   "es": "Español",
-  "gd": "Gàidhlig",
   "it": "Italiano",
-  "pl": "Polski",
   "sv": "Svenska"
 }