Pontoon: Update Icelandic (is) localization of AMO Frontend
Pontoon: Update Icelandic (is) localization of AMO Frontend

Co-authored-by: Peiying Mo [:CocoMo] <649b7cf324f6ebae0499249a6dc2f67faa69dd98@mozilla.com>
Co-authored-by: Sveinn í Felli <30a262ee0cddf15a17abb23e11148aa362a8bb02@fellsnet.is>

mozilla/addons-frontend,mozilla/addons-frontend,mozilla/addons-frontend,mozilla/addons-frontend