Translate devices.js, dashboard.js and added new keys

src/strings/en-us.json

@@ -1473,5 +1473,6 @@
     "PathNotFound": "The path could not be found. Please ensure the path is valid and try again.",
     "WriteAccessRequired": "Jellyfin Server requires write access to this folder. Please ensure write access and try again.",
     "ListPaging": "{0} of {1}",
-    "PersonRole": "as {0}"
+    "PersonRole": "as {0}",
+    "LastSeen": "Last seen {0}"
 }

src/strings/es.json

@@ -1481,5 +1481,6 @@
     "PathNotFound": "No se encontró la ruta especificada. Asegúrate de que existe e inténtalo de nuevo.",
     "WriteAccessRequired": "Jellyfin requiere de permisos de escritura en esta carpeta. Asegúrate de que existe este permiso e inténtalo de nuevo.",
     "ListPaging": "{0} de {1}",
-    "PersonRole": "como {0}"
+    "PersonRole": "como {0}",
+    "LastSeen": "Última vez {0}"
 }