Add filter for discarded products

Changes include:
- Addition of new filter in `filters` method in the products index component,
  now includes an additional filter for 'with_discarded' products.

Please note that this is a special case of filters in the context of
transitioning from the old to the new products index page.
This change ensures that the feature set between the old and new product index
page remains consistent.

Co-Authored-By: Elia Schito <[email protected]>

admin/app/components/solidus_admin/products/index/component.rb

@@ -48,7 +48,13 @@ def batch_actions
   end
 
   def filters
-    []
+    [
+      {
+        name: 'q[with_discarded]',
+        value: true,
+        label: t('.filters.with_deleted'),
+      },
+    ]
   end
 
   def columns

admin/app/components/solidus_admin/products/index/component.yml

@@ -12,3 +12,5 @@ en:
     delete: 'Delete'
     discontinue: 'Discontinue'
     activate: 'Activate'
+  filters:
+    with_deleted: Include deleted