Adding Vietnamese as a new language (beta) (#24074)

* adding vietnamese

* ran npm run test:updatesnapshot

* ran npm run test:updatesnapshot

* Update i18n.jsx

* updatesed snapshot

* fix whitespace in snapshots

* add vi as supported server locale

* update docs to point at server-side list of supported locales

* removed incorrect translation

---------

Co-authored-by: Tom De Moor <tom@controlaltdieliet.be>
Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Jesse Hallam <jesse.hallam@gmail.com>

server/public/shared/i18n/i18n.go

@@ -49,6 +49,7 @@ var supportedLocales = []string{
 	"pt-BR",
 	"ro",
 	"sv",
+	"vi",
 	"tr",
 	"bg",
 	"ru",