Include Vietnamese language (#20029)

* Include Vietnamese language

https://translate.element.io/languages/vi/element-web/ has been professionally translated by an Element customer

* Vietnamese -> "Tiếng Việt" ("Vietnamese Language")

scripts/copy-res.js

@@ -53,6 +53,7 @@ const INCLUDE_LANGS = [
     {'value': 'th', 'label': 'ไทย'},
     {'value': 'tr', 'label': 'Türkçe'},
     {'value': 'uk', 'label': 'українська мова'},
+    {'value': 'vi', 'label': 'Tiếng Việt'},
     {'value': 'vls', 'label': 'West-Vlaams'},
     {'value': 'zh_Hans', 'label': '简体中文'}, // simplified chinese
     {'value': 'zh_Hant', 'label': '繁體中文'}, // traditional chinese