helios: Do not used target name in popup.

Helios could not be opened in brave if it is.

index.js

@@ -6,7 +6,7 @@ define(["require"], function (require) {
             return require.toUrl('./index.html') + "#" + encodeURIComponent(a.href);
         },
         popup: function () {
-            window.open(this.pageUrl(), "Helios", "menubar=no, width=1000, height=600");
+            window.open(this.pageUrl(), undefined, "menubar=no, width=1000, height=600");
         },
         go: function () {
             window.location.href = this.pageUrl();