perf(solidus_admin): Remove distinct from product scopes

The distinct isn't necessary, because the result will be put into an IN filter and there is no reason to filter out possible duplicates. It slows only the query.

Author: sascha-karnatz

admin/app/controllers/solidus_admin/products_controller.rb

@@ -8,8 +8,8 @@ class ProductsController < SolidusAdmin::BaseController
     search_scope(:deleted) { _1.with_discarded.discarded }
     search_scope(:discontinued) { _1.where(discontinue_on: ...Time.current) }
     search_scope(:available) { _1.available }
-    search_scope(:in_stock) { _1.where(id: Spree::Variant.in_stock.distinct.select(:product_id)) }
-    search_scope(:out_of_stock) { _1.where.not(id: Spree::Variant.in_stock.distinct.select(:product_id)) }
+    search_scope(:in_stock) { _1.where(id: Spree::Variant.in_stock.select(:product_id)) }
+    search_scope(:out_of_stock) { _1.where.not(id: Spree::Variant.in_stock.select(:product_id)) }
 
     def index
       products = apply_search_to(