UX: hide associate accounts if second factor is enabled

Once second factor is enabled all login via associated accounts is banned
showing this section just leads to confusion

test/javascripts/controllers/preferences-account-test.js.es6

@@ -0,0 +1,21 @@
+moduleFor("controller:preferences/account");
+
+QUnit.test("updating of associated accounts", function(assert) {
+  const controller = this.subject({
+    siteSettings: {
+      enable_google_oauth2_logins: true
+    },
+    model: Em.Object.create({
+      second_factor_enabled: true
+    }),
+    site: Em.Object.create({
+      isMobileDevice: false
+    })
+  });
+
+  assert.equal(controller.get("canUpdateAssociatedAccounts"), false);
+
+  controller.set("model.second_factor_enabled", false);
+
+  assert.equal(controller.get("canUpdateAssociatedAccounts"), true);
+});