[Representation] Destroy scopes before adding

Destroy representation scope before adding elements back into
the DOM; avoids having a momentary activation of watches and
listeners on those scopes before they are replaced with newly
compiled content for new scopes.

platform/representation/src/TemplateLinker.js

@@ -132,6 +132,7 @@ define(
 
             function changeTemplate(templateUrl) {
                 if (templateUrl) {
+                    destroyScope();
                     addElement();
                     self.load(templateUrl).then(function (template) {
                         // Avoid race conditions