Pontoon: Update Vietnamese (vi) localization of Firefox Screenshots
Pontoon: Update Vietnamese (vi) localization of Firefox Screenshots

Localization authors:
- Quế Tùng <best.cloney.1301@gmail.com>

mozilla-services/pageshot,mozilla-services/pageshot,mozilla-services/screenshots,mozilla-services/pageshot,mozilla-services/screenshots,mozilla-services/screenshots,mozilla-services/screenshots,mozilla-services/pageshot