fix(test): mock scrollTo dom-helper utility in tests (#437)

Author: Austin Green

__mocks__/dom-helpers/util/scrollTo.js

@@ -0,0 +1,14 @@
+/**
+ * Copyright Zendesk, Inc.
+ *
+ * Use of this source code is governed under the Apache License, Version 2.0
+ * found at http://www.apache.org/licenses/LICENSE-2.0.
+ */
+
+/**
+ * Mock `scrollTo` implementation
+ * @param {*} domNode
+ */
+export default function scrollTo(domNode) {
+  return undefined;
+}