fix commerce service for cart

adapt cart from current page instead of resource to make it work for components used within the template

ui.apps/src/main/content/jcr_root/apps/we-retail/components/structure/navcart/cart.js

@@ -22,7 +22,7 @@ var global = this;
  */
 use(function () {
 
-    var commerceService = resource.adaptTo(com.adobe.cq.commerce.api.CommerceService);
+    var commerceService = currentPage.getContentResource().adaptTo(com.adobe.cq.commerce.api.CommerceService);
     var session = commerceService.login(request, response);
     var resolver = resource.getResourceResolver();
 
@@ -68,4 +68,4 @@ use(function () {
         total: total,
         entries: _entries
     }
-});
+});