[FIX] website_sale: set border color on color attribute

The border color of 'color' filter attribute on /shop page corresponds
to the color od the body which makes it difficult for users to see the
color they selected.

task-3584558

closes odoo#141461

Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>

addons/website_sale/static/src/scss/website_sale.scss

@@ -3,6 +3,7 @@
 // use of an ugly overflow: hidden which would break box-shadows.
 $o-wsale-products-layout-grid-gutter-width: $grid-gutter-width / 2 !default;
 $o-wsale-products-layout-grid-gutter-width: min($grid-gutter-width / 2, $o-wsale-products-layout-grid-gutter-width);
+$input-border-color: $gray-400;
 
 @mixin wsale-break-table($-list: false) {
     .o_wsale_products_grid_table_wrapper {