Upgrade underscore to newest version.

FEDX-24

common/static/js/src/string_utils.js

@@ -21,7 +21,7 @@
      */
     var interpolate_ntext = function (singular, plural, count, values) {
         var text = count === 1 ? singular : plural;
-        return _.template(text, values, {interpolate: /\{(.+?)\}/g});
+        return _.template(text, {interpolate: /\{(.+?)\}/g})(values);
     };
     this.interpolate_ntext = interpolate_ntext;
 
@@ -42,7 +42,7 @@
      * @returns the text with placeholder values filled in
      */
     var interpolate_text = function (text, values) {
-        return _.template(text, values, {interpolate: /\{(.+?)\}/g});
+        return _.template(text, {interpolate: /\{(.+?)\}/g})(values);
     };
     this.interpolate_text = interpolate_text;
 }).call(this, _);