WelcomeSurvey: Use autonyms for language question

For the tags in the tag widget, use autonyms rather than translated
language names.

This also makes the meta=languageinfo API request obsolete, since we can
use $.uls.data.getAutonyms() to get all the information we need.
Removing the API request reduces the time it takes before the lanugage
question widget loads.

Bug: T232410
Change-Id: I43101bb597da9aff41bf281861a3c126b1fb45d4
(cherry picked from commit b93dfc1c9ed1a8bce2946e5afb9554d31d87fbd5)