Add Korean localization for Dashboard (#4174)

* Add Korean i18n for Dashboard

* Update for outdated in Korean translation

* Update for Korean translation

i18n/locale_conf.json

-{"translations": [ "en", "fr", "ja", "zh" ]}
+{"translations": [ "en", "fr", "ja", "ko", "zh" ]}

package.json

@@ -85,6 +85,7 @@
     "languages": [
       "fr",
       "ja",
+      "ko",
       "zh"
     ],
     "beautifyOutput": true