For stability of puppeteer tests, ensure the dropdown doesn't flip up

public/index.html

@@ -841,6 +841,7 @@ <h2>Form interaction</h2>
           document.getElementById('choices-single-custom-templates'),
           {
             allowHTML: true,
+            position: 'bottom',
             callbackOnCreateTemplates: function(strToEl) {
               var classNames = this.config.classNames;
               var itemSelectText = this.config.itemSelectText;