fix: Sub-Categpry Routing in Item Group Page Listing pills

- Use absolute route even 3-4 sub-category levels down
- Remove scroll from category pills due to accessibility issues
- Arrange sub-category pills alphabetically

erpnext/e_commerce/product_ui/views.js

@@ -495,7 +495,7 @@ erpnext.ProductView =  class {
 
 			categories.forEach(category => {
 				sub_group_html += `
-					<a href="${ category.route || '#' }" style="text-decoration: none;">
+					<a href="/${ category.route || '#' }" style="text-decoration: none;">
 						<div class="category-pill">
 							${ category.name }
 						</div>