[FIX] product_extended: traceback on `bom_count`

The field `bom_count` is added in the view for group `group_mrp_user`.
Therefore when extending the view, we should make sure to restrict the
access as well.

opw-679172

addons/product_extended/product_extended_view.xml

@@ -6,6 +6,7 @@
             <field name="model">product.template</field>
             <field name="priority">3</field>
             <field name="inherit_id" ref="product.product_template_only_form_view" />
+            <field name="groups_id" eval="[(4, ref('mrp.group_mrp_user'))]"/>
             <field name="arch" type="xml">
                 <div name="standard_price_uom" position="after">
                     <button name="%(action_view_compute_price_wizard)d"
@@ -19,4 +20,3 @@
         </record>
     </data>
 </openerp>
-