Removing the apply in the CatalogFilterPaginationSpecification

- This is so I can commit this to the repo as an example.

src/ApplicationCore/Specifications/BaseSpecification.cs

@@ -45,6 +45,7 @@ namespace Microsoft.eShopWeb.ApplicationCore.Specifications
             OrderByDescending = orderByDescendingExpression;
         }
 
+        //Not used anywhere at the moment, but someone requested an example of setting this up.
         protected virtual void ApplyGroupBy(Expression<Func<T, object>> groupByExpression)
         {
             GroupBy = groupByExpression;

src/ApplicationCore/Specifications/CatalogFilterPaginatedSpecification.cs

@@ -9,7 +9,6 @@ namespace Microsoft.eShopWeb.ApplicationCore.Specifications
                 (!typeId.HasValue || i.CatalogTypeId == typeId))
         {
             ApplyPaging(skip, take);
-            ApplyGroupBy(i => new { i.CatalogType });
         }
     }
 }