[FIX] product: disable "create & edit" shotcut for product variants

With the purchase module, when you create a new vendor, you can
select what variant of the product the vendor sells. The droplist
has the "Create & Edit" button to quickly create/edit variants.
This is not the wanted behavior. This PR removes the "Create & Edit"
suggestion.

opw-1909009

closes odoo#28845

addons/product/views/product_views.xml

@@ -520,7 +520,7 @@
                     <group>
                         <group string="Vendor">
                             <field name="product_variant_count" invisible="1"/>
-                            <field name="product_id" groups="product.group_product_variant" domain="[('product_tmpl_id', '=', product_tmpl_id)]"/>
+                            <field name="product_id" groups="product.group_product_variant" domain="[('product_tmpl_id', '=', product_tmpl_id)]" options="{'no_create_edit': True}"/>
                             <field name="name" context="{'default_customer': 0, 'search_default_supplier': 1, 'default_supplier': 1}"/>
                             <field name="product_name"/>
                             <field name="product_code"/>