[FIX] product: Hide product variant field if option not actived

Purpose
=======

If the group_product_variant is not activated, the field should be hidden

addons/product/views/product_views.xml

@@ -559,7 +559,7 @@
                 <tree string="Vendor Information">
                     <field name="sequence" widget="handle"/>
                     <field name="name"/>
-                    <field name="product_id" invisible="context.get('product_template_invisible_variant', False)"/>
+                    <field name="product_id" invisible="context.get('product_template_invisible_variant', False)" groups="product.group_product_variant"/>
                     <field name="product_tmpl_id" string="Product" invisible="context.get('visible_product_tmpl_id', True)"/>
                     <field name="min_qty"/>
                     <field name="price" string="Price"/>