[FIX] pos_mercury: Fix duplicate xml id

Follow up on https://github.com/odoo/odoo/commit/63f052a40072e3a5487a8fe61c29f29d48807334#r34578119
Due to this https://github.com/odoo/odoo/blob/12.0/addons/pos_mercury/views/pos_config_setting_views.xml#L3

 was being replaced by this view (See manifest for info)

closes odoo/odoo#35471

Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>

addons/pos_mercury/views/pos_config_views.xml

 <?xml version="1.0" encoding="utf-8"?>
 <odoo>
-    <record id="pos_config_view_form_inherit_pos_mercury" model="ir.ui.view">
+    <!-- TODO the inherit for
+         point_of_sale.res_config_settings_view_form in this module
+         uses the pos_config_view_form_inherit_pos_mercury xml id
+         already. It should be renamed to
+         res_config_settings_view_form_inherit_pos_mercury. -->
+    <record id="pos_config_view_form_inherit_pos_mercury_2" model="ir.ui.view">
         <field name="name">pos.config.form.view.inherit.mercury</field>
         <field name="model">pos.config</field>
         <field name="inherit_id" ref="point_of_sale.pos_config_view_form"/>