fix: remove sortkey 'default' from product list REST calls to prevent…

… inconsistent results (#1550)

The "sortKey" and "sorting" parameter is set to "default" when the "Default Sorting" option is selected via dropdown. This leads to incorrect sorting of the products, as this "default" parameter is not an existing sorting key.

src/app/core/services/products/products.service.ts

@@ -76,7 +76,7 @@ export class ProductsService {
       .set('offset', offset.toString())
       .set('returnSortKeys', 'true')
       .set('productFilter', 'fallback_searchquerydefinition');
-    if (sortKey) {
+    if (sortKey && sortKey !== 'default') {
       params = params.set('sortKey', sortKey);
     }
 
@@ -129,7 +129,7 @@ export class ProductsService {
       .set('attrs', STUB_ATTRS)
       .set('attributeGroup', AttributeGroupTypes.ProductLabelAttributes)
       .set('returnSortKeys', 'true');
-    if (sortKey) {
+    if (sortKey && sortKey !== 'default') {
       params = params.set('sortKey', sortKey);
     }
 
@@ -174,7 +174,7 @@ export class ProductsService {
       .set('attrs', STUB_ATTRS)
       .set('attributeGroup', AttributeGroupTypes.ProductLabelAttributes)
       .set('returnSortKeys', 'true');
-    if (sortKey) {
+    if (sortKey && sortKey !== 'default') {
       params = params.set('sortKey', sortKey);
     }
 
@@ -205,7 +205,7 @@ export class ProductsService {
       .set('attrs', STUB_ATTRS)
       .set('attributeGroup', AttributeGroupTypes.ProductLabelAttributes)
       .set('returnSortKeys', 'true');
-    if (sortKey) {
+    if (sortKey && sortKey !== 'default') {
       params = params.set('sortKey', sortKey);
     }
     params = appendFormParamsToHttpParams(omit(searchParameter, 'category'), params);