[FIX] hr_maintenance: use hr.employee -> .public when missing rights

Steps to reproduce
==================

- Login as a user with no rights
- Use a mobile viewport
- Create a new Maintenance Request
- Edit the Created By field

-> A traceback occurs because the user has no rights

Solution
========

We extend the Many2OneField to accept a relation option and Depending on
whether the user has the rights, use the correct one.

This is similar to 41eaff0f

opw-3430105

closes odoo/odoo#132197

Signed-off-by: Sofie Gvaladze (sgv) <sgv@odoo.com>

addons/hr_maintenance/views/maintenance_views.xml

@@ -26,7 +26,13 @@
         <field name="arch" type="xml">
             <xpath expr="//field[@name='owner_user_id']" position="replace">
                 <field name="employee_id" string="Created By"
-                       options="{'no_create_edit': True, 'no_open': True}"/>
+                       widget="many2one_avatar_employee"
+                       options="{'no_create_edit': True, 'no_open': True, 'relation': 'hr.employee.public'}"
+                       groups="!hr.group_hr_user"/>
+                <field name="employee_id" string="Created By"
+                       widget="many2one_avatar_employee"
+                       options="{'no_create_edit': True, 'no_open': True, 'relation': 'hr.employee'}"
+                       groups="hr.group_hr_user"/>
             </xpath>
         </field>
     </record>